Isaac

Isaac (Robin in the Japanese version) is a Venus Adept, a playable character in Golden Sun and Golden Sun: The Lost Age, and a main character in the overall Golden Sun series. He is the silent protagonist and party leader of the original Golden Sun, and gains a speaking role in his appearance late in Golden Sun: The Lost Age as a co-leader of the game's extended final party. For being the most effective "main representative" of the Golden Sun series, Isaac serves a cameo role in the 2008 Nintendo fighting game, Super Smash Bros. Brawl.

=As a playable character= Throughout all of Golden Sun, Isaac serves the most important gameplay role for the player in the game: he is the player. More specifically, he is the character who the player controls in the game's overworld and field-style environments and is the one who initiates conversations with Non-Player Characters and searches aspects of the environment. He is the "party leader" in Golden Sun, which means that as he leads a group of Adept companions through the game's plot and world progression, he is the only character among them who is actually visible as you control him and have him walk and run through the world's locales. Also signifying Isaac's role as party leader in the first game is his in-game depiction as a fully silent protagonist while his companions that appear in cutscenes engage in conversations for him. Isaac is not actually a muted character or a man-of-few-words in the actual story of the game; that is merely how he is depicted when under the control of the player for the whole game.

Another thing that comes with Isaac's role as party leader is his inherent knowledge of two particular Utility Psynergy spells: Move, the ability to remotely move an object in any one of the four compass directions, and Retreat, the ability to instantaneously teleport himself and everyone in his party out of almost any point in a dungeon-style location to that location's entrance point. The Venus Adept and party leader in Golden Sun: The Lost Age, Felix, begins the game inherently knowing these Psynergy spells as well.

In Golden Sun Isaac is present for every battle sequence that takes place. In fact, the game's prologue has the player controlling a younger Isaac that is weaker and has no Psynergy at all. The "normal" Isaac is controllable following the prologue sequences when starting off at the town Vale. Isaac is a warrior-style Venus Adept, which makes his inherent class series the Squire class series, and when the player first controls him he is level 1, has no Djinn, and is initially equipped with a Short Sword, Cotton Shirt, and Padded Gloves. Over the course of the game, Isaac should prove the best fighter of the party of Adepts he leads, being both stronger and faster than the Mars Adept warrior Garet he fights alongside with.

Isaac, like the rest of his party, is absent from your own party as led by Felix, Isaac's very similar Venus Adept counterpart, for much of Golden Sun: The Lost Age. At a late point in the game, Isaac's party joins Felix's as additional party members, and the statistics and inventory of Isaac as well as his companions Garet, Ivan, and Mia are directly dependent on whether you're using data transfer, what level of data transfer you're using, and the actions and levels of progress Isaac's party committed in the previous game.

If there is no data transfer used at all, Isaac will join at level 28, with five of the original game's 28 Djinn (instead of seven) Set onto him, and he will be equipped with a Great Sword, Knight's Shield, Knight Helm, and Steel Armor. Also in his inventory will be all the Utility Psynergy items the party is required to collect to reach the end of the first Golden Sun, without any of the items the party can potentially miss - namely, he'll have the Catch Beads, Carry Stone, Lifting Gem, Douse Drop, and Frost Jewel, and will be missing the Orb of Force, Cloak Ball, and Halt Gem. If a Bronze-level password is used for data transfer, Isaac's level, amount of Djinn set on him, and whether the party has collected the last three Utility Psynergy items listed above will be transfered between his last appearance in that game and his first appearance in this game. Using a Silver-level password will achieve the Bronze password's effects along with transfering any permanent statistics boosts Isaac may have gotten from using items like Cookies and Mints. The Gold-level password will do the same thing as the Silver password in addition to Isaac having in his inventory every item and piece of equipment he had in his inventory at the end of the last game, albeit currently unequipped. Finally, using a Game Link cable to transfer data directly and quickly will achieve the same effect as the Gold-level password, with Isaac now equipped with the items and Set Djinn in his inventory exactly the way he was the last game.

Isaac easily has the exact same amount of potential as his Venus warrior counterpart Felix to be the best fighter in The Lost Age, and they share a trait that can make either of them far more powerful than the rest of the Adepts: The ability to equip the ultimate weapon, Sol Blade.

In Super Smash Bros. Brawl
Isaac is the only character from the Golden Sun series making a cameo appearance in another Nintendo video game, in this case the popular Wii fighting game Super Smash Bros. Brawl, which is his first 3D appearance in a console game. While Isaac is not a playable character, he serves a minor gameplay role by being one of dozens of minor computer-controlled Nintendo characters that can be randomly summoned during battle by the item called the Assist Trophy. If Isaac appears out of an Assist Trophy, he will cast the Move Psynergy three times in succession while yelling, each time calling up a giant gloved hand that shoots forward to push away and off the stage any fighter that is an opponent of the fighter who summoned Isaac. He will automatically turn around to face the direction of valid targets in between his castings based on how many fighters are to his left or his right. Consensus among Smash Bros. fans place Isaac as one of the strongest Assist Trophy characters in the game.

Everything serving a gameplay role in Brawl is represented by collectible figurines called Trophies, of which hundreds exist, and each trophy showcases a 3D model of a character, object, or other property along with a short text description. Isaac is no exception, and his trophy is among the large proportion of trophies that can be collected by "normal means" in Brawl, such as in a trophy-collecting mini-game called the Coin Launcher. Its text description reads:

"A strong-willed Psynergy adept of the bloodline of an ancient race thought to have been lost with the downfall of civilization. He can manipulate earth-based forces and is also a highly skilled swordsman. He sets out to protect a lighthouse that can release the sealed powers of alchemy. In Smash Bros., he uses "Move" energy, which creates an energy field that pushes foes away."

=Biography= Isaac was born in the secluded town of Vale at the base of the dormant volcano Mt. Aleph, and for his first fourteen years he lived a tranquil life there with his parents Kyle and Dora and his friends Garet, Jenna, and Felix. Like his parents, Isaac is a Venus Adept, and all the townspeople of Vale are Adepts to varying degrees because they live their lives under the influence of a giant Psynergy Stone formation near the town's entrance. Isaac was very reliable and was well-liked by the populace; as an individual, he is virtuous and caring yet not to a fault, and Dora describes him as being so much like his father at his age, including his stubbornness. Isaac used to visit the cottage of the scholar Kraden a lot as well.

Having lived at Vale his entire life, at a mountainous area not close enough to the Great Western Sea, Isaac has never seen an ocean before, like his friends at that point.

In Golden Sun
The story of the first Golden Sun is told through Isaac's perspective, so Isaac is the main character the player controls throughout the entire game, and becomes the silent protagonist the player may end up interpreting his or her own way.

The Mt. Aleph Boulder incident
The lives of Isaac and many others were changed forever when he was fourteen, when the Mt. Aleph Boulder incident happened at Vale: A terrible thunderstorm struck Mt. Aleph and Vale, and a giant boulder located somewhere on Mt. Aleph named the Mt. Aleph Boulder became dislodged and descended upon Vale. As groups of Valeans attempted to hold back the boulder with their Psynergy, Kyle and Dora helped evacuate the townspeople as Isaac went with them, but then they saw that Felix had fallen into the town's river and was hanging on a pole in the water desperately for life. Kyle joined Felix's father and mother as they tried in vain to help Felix get back ashore.

But then the boulder began its fateful course through Vale like an instrument of mass destruction, and Isaac's father seemingly disappeared with Felix and his parents as the boulder plowed its way through their position and off the edge of the nearby waterfall. Lost and confused, Isaac wandered off on his own and Garet followed him, and they soon encountered a pair of menacing strangers in the night, Saturos and Menardi, who used their powerful Mars Psynergy to knock Isaac and Garet out cold so they would forget their memories of the pair as they left the area.

Needless to say, the period of time following the disaster was very trying for Isaac and those he knew. Isaac and Dora were devestated by the apparent death of Kyle, but that was small-scale compared to the trauma Jenna underwent as she had apparently lost her entire family. Isaac and Garet resolved to study the art of Psynergy hard over the next three years, with Kraden guiding their toils as a scholar of Alchemy himself, to become stronger both for themselves and for everyone else.

Infiltrating Sol Sanctum
In the present age, Isaac has become a strong, reliable young man who has developed his Psynergy powers as a Venus Adept, along with Garet and Jenna. One day, as part of their studies, Kraden arranges for an expedition into Mt. Aleph's shrine, Sol Sanctum, with the three young Adepts and himself. Totally by coincidence, however, Saturos and Menardi return to Vale that day, audibly plotting on how to enter the Sol Sanctum themselves; when Isaac and his friends encounter them, a brief but tense interaction ensues (Isaac and Garet wouldn't remember the pair of Mars Adepts from three years ago since the memory was physically knocked out of them), but Saturos decides to let them pass. Isaac and company go to Kraden to speak about the strangers, and conclude they are likely here to rob the Sanctum, but they cannot prove that until after they commence their own scheduled expedition, which they do immediately.

Isaac and Kraden lead their group as they secretly enter Sol Sanctum and eventually make it into the sealed chamber where the Elemental Stars await on their respective pedestals. Perhaps letting his curiosity overtake his better judgment, Kraden orders Isaac and Garet to remove and retrieve the Elemental Stars for him to study. Just as Isaac and Garet collect three of the four Stars, fate intervenes and Saturos and Menardi make an entrance and take Jenna and Kraden hostage, demanding that Isaac and Garet hand over the Elemental Stars. This time, the pair has other companions with them: A powerful Mercury Adept named Alex and, to everyone's disbelief, none other than Felix himself, who Saturos and Menardi had rescued from the disaster three years back and who now is sworn to their cause. Isaac and Garet have no choice but to comply with their orders, giving them their three Stars and heading to retrieve the fourth for them.

When Isaac and Garet remove the last Star, the Mars Star, from its pedestal, fate throws a dramatic twist at all involved as the volcano that is Mt. Aleph begins to stir, and a boulder-like entity laced with immense power awakens and makes its presence known. When Kraden identifies the being as none other than the Wise One from the healer's tales at Vale, Saturos' group realizes it is too dangerous to remain here here and are forced to make a personally troubling decision: to take a tremendous but unavoidable risk by leaving Isaac, Garet, and the Mars Star behind at the volcano while they flee with their own lives. Saturos needs all four Stars to carry out his group's plan to activate the four Elemental Lighthouses and therefore restore the force of Alchemy to the world, so they decide to take Jenna and Kraden with them as part of their group. Saturos' group can only hope that Isaac will escape on his own, because if he does he will immediately pursue them in an attempt to free Jenna and Kraden from their grasp, and Isaac meeting them this way would give Saturos the opportunity relieve the Mars Star from Isaac's possession in the future.

Isaac and Garet, meanwhile, personally come face-to-eye with the monolithic Wise One, who declares to them that if the Elemental Lighthouses are lit, the world will be exposed to the threat of Alchemy. The Wise One explains that Alchemy can be a dangerous power if misused by the people of Weyard, so the lighthouses should remain unlit and Saturos' objective should be thwarted for the sake of the world's safety. As the volcano erupts, the Wise One uses his powers to subtly imbue the Mars Star in Isaac's possession with an as-of-yet unknown property for an as-of-yet unknown purpose, then teleports Isaac and Garet to safety so that they can return to Vale alive. The Wise One redirects the flow of lava from the volcano away from the town, saving everyone there.

Isaac and Garet attend as the main subjects of an urgent town meeting in Vale's Sanctum, and they explain to the worried townsfolk everything that happened to them and to Jenna and Kraden. The Great Healer at the Sanctum affirms their story by telepathic messages he receives from the Wise One, and declares that the fate of the world will be dependent on whether Isaac and Garet will take up the quest to pursue and stop Saturos' group or not, but the decision on whether to take up this incredible responsibility will ultimately lie with Isaac and Garet individually. Garet is quick to leave his decision to Isaac, so Isaac must now decide for them both. Should Isaac refuse to accept the burden of the entire world as his own, he will not be able to take back his decision as he leaves the sanctum and the town. Thus would Weyard begin drifting towards its fated destruction.

In the canonical version of the game's story, Isaac does accept the immense responsibility of taking the fate of the world in his hands. The Wise One telepathically compliments Isaac and Garet's bravery for taking up his quest and instructs them to choose their destinies wisely. Isaac and Garet do not receive many detailed instructions on how to start their quests off, however. Everyone decides for Isaac and Garet to spend one last night with their families at Vale, and then see them off as they start their journey the next day. Dora is too distraught to actually be there to see her son off on such a dangerous mission, so Isaac receives Dora's Catch Beads from Garet's brother Aaron in Dora's place. Isaac's great adventure across Weyard to save the world from the destructive force of Alchemy and to rescue Jenna and Kraden from the villains now begins.

Mercury Lighthouse
Isaac and Garet initially don't have a specific location or direction in mind when they begin their hasty quest in pursuit of Saturos' party across the continent of Angara. Immediately after they leave Vale for the first time in either of their lives, they start battling and killing off many, many wild monsters that now roam the lands and attack passersby thanks to the influence Mt. Aleph's eruption had on the world, and the battling experience Isaac and Garet receive increases their proficiency at fighting and sharpens their Psynergy abilities somewhat dramatically. Isaac also meets and befriends the Venus Djinni Flint almost immediately on his quest, and Flint is the first of many elemental Djinn Isaac's group will collect over their quest.

The first town Isaac and Garet come across is Vault, where they meet a mysterious young Jupiter Adept named Ivan. They help him retrieve an important artifact, the Shaman's Rod, that was stolen from him by the Vault gang of thieves, as well as witnessing the first a part of a subplot involving the merchant Hammet and the towns Kalay and Lunpa. Ivan, using his ability to read minds to learn everything that happened to Isaac and Garet and how it relates to the world's fate, eventually decides to join Isaac on his quest and becomes a permanent component of Isaac's traveling group of Adepts from then on.

The course of Isaac's quest eventually leads them to the wintry northern region of Angara, where the town Imil resides a short distance away from the Elemental Lighthouse of Mercury. Since this is the closest Lighthouse to Vale geographically, it would make sense that this would be Saturos' first target. As Isaac's group passes through Imil, they spot a female Mercury Adept and healer named Mia, who goes to Mercury Lighthouse concerned that there might be invaders who have infiltrated. Isaac accompanies her and removes some obstacles with his Psynergy, to Mia's surprise because she wasn't aware there were other Adepts like herself and Alex, who she knew until recently. Mia joins Isaac's party and the four of them climb their way up the tower to find the ones who might be here and to make sure the Lighthouse's beacon is not activated.

At the aerie of Mercury Lighthouse, they discover to their great dismay that the Mercury Beacon has already been activated with the Mercury Star, a process which cannot be reversed by any known means. The culprits haven't left yet: Menardi and Felix call out to them from the opposite end of the aerie, and Saturos himself soon steps in front of the Adepts, ready to defeat the Adepts in battle and take the Mars Star for himself as the others flee. A fierce battle indeed, but the active lighthouse's Mercury element suppresses Saturos' Mars-based powers enough that Isaac's party is actually able to best him in battle. Alex, who was watching the Adepts from afar, makes himself known at this point, commenting on how Isaac and his group have become such great fighters in such a short amount of time, before helping Saturos up and leaving with him as they resume their objective to activate the rest of the Lighthouses. Isaac's party resolves to resume their quest to stop Saturos in much the same fashion, with Mia accompanying them as a permanent party member. Isaac's group is now fully rounded out with four members, one of each element.

Quest across two continents
Isaac leads his group of Adepts, consisting of himself, Garet, Ivan, and Mia, clockwise across the entire continent of Angara in pursuit of Saturos' group of Adepts and unwilling captives, all the while entering new towns, exploring and clearing dungeons and caves whose obstacles and wild monsters challenge Isaac's course, and playing his party's role in several subplots involving characters like the young woman Feizhi and the oracle Hama. By the time his band makes it to the town of Kalay, Isaac's group has an opportunity to revisit Vale and temporarily reunite with Isaac's mother Dora (who has grown ill with a cold out of worry over her son's safety) and Garet's family. Knowing now that Saturos crossed the Karagol Sea southwest of Angara to the continent of Gondowan where the next lighthouse, Venus Lighthouse, awaits to be lit, Isaac's group takes a none-too-pleasant voyage on the ferry service across the sea, arriving at Gondowan and beginning the next leg of their quest.

The biggest and most prosperous city in all of known Weyard is Tolbi, which is Isaac's first stop in Gondowan, and its world-famous annual festival and tournament of warriors, Colosso, is in full swing. But Tolbi's mysterious ruler, Lord Babi, is missing. Exploring the nearby Altmiller Cave, Isaac & Co. discover Babi on the verge of death and save his life by bringing him the vial of fluid Babi was seeking in the cave to find and drink, which is the last of the Lemurian Draught Babi had stockpiled in the cave. Babi takes a keen interest in Isaac and his company's powers as Adepts like he himself is, and decides to personally register Isaac as a Colosso gladiator for the upcoming Colosso Finals so he may see Isaac's abilities as a warrior in action. Isaac and his friends agree and he competes in the competition exceedingly well, well enough that Babi decides he has finally found the group of warriors he has been seeking all these years.

Babi explains everything to Isaac's group afterwards: Long ago he was at the mythical, hidden island city and society of Lemuria far out in the Great Eastern Sea, shrouded by fog and a ring of stone crags, and using the Psynergy he learned there he fled the isle on a Lemurian Ship with a large stockpile of Lemurian Draught in tow. Drinking this fluid extends his life beyond his normal years, and at this point Babi has lived 150 years now. But his draught stockpile has run out, and he needs a group of Adepts like Isaac to commandeer his Lemurian Ship into the ocean and make it into Lemuria somehow to retrieve more draught for him so that he may live. Babi hid his Lemurian Ship within the town Lalivero in the easternmost region of Gondowan, which is near the Venus Lighthouse, which is Isaac's next destination at any rate, and Babi also had ordered the construction of a tower named Babi Lighthouse near Lalivero so that the powerful light it would illuminate at night would help orient sailors like Isaac as they try to enter the foggy area of sea where Lemuria is hidden. With this in mind, Isaac promises Babi that once he has achieved his own objective to stop Saturos' group for good before they can activate the Venus Lighthouse, he and his party will search for Lemuria and attempt to save Babi's life again. Babi assigns his chief minister, Iodem, to accompany Isaac as they travel to Lalivero and the Venus Lighthouse.

Venus Lighthouse
Isaac's party journeys to Lalivero with Iodem, but finds from the distressed locals that Saturos' group passed through here with a young Laliveran girl named Sheba as yet another one of their captives. Iodem and Isaac can only speculate what they would want with Sheba, but Isaac leaves Iodem behind with the Laliverans as he and his companions scale the nearby Venus Lighthouse; at this point they possess the power and Psynergy ability necessary that they can actually solve the structure's ancient riddles and scale it to the structure's top, and that Isaac does, intent on ending Saturos' objective to unleash Alchemy for good.

At the Venus Lighthouse Aerie, they make it just in time as Saturos and Menardi, in front of the Lighthouse's unlit beacon, have a falling out with Felix over the involvement of Sheba in their quest, who is up there with them. Isaac's party confronts Saturos and Felix, and a tense standoff occurs where Saturos threatens to harm Sheba unless Ivan gives Saturos the Shaman's Rod in his possession. Isaac and Ivan agree to his terms, assuming that Saturos means he would free Sheba from their hold once they have the rod, but Saturos clarifies afterwards that he only said he wouldn't let harm come to her, to Isaac's party's exasperation. Sheba, after all, is actually a Jupiter Adept, and Saturos' group needs both her and the Shaman's Rod in order to properly scale the next lighthouse in the future, the Jupiter Lighthouse. Saturos and Menardi then decide it is time for Isaac's party to die, and they launch an all-out offensive against his group, but after a fierce battle Isaac eventually bests the pair of master Mars Adepts in combat.

Isaac then tries to reason with Felix, but Felix insists that the Lighthouse beacons must still be lit, forcing Isaac to conclude that Felix is their enemy. But Saturos and Menardi are not out of the picture yet: they casually toss the Venus Star into the Venus Lighthouse's well, to Isaac's horror. As the Venus Lighthouse activates, the structure's energy recharges the pair even though they are Mars Adepts, because Mars and Venus are symbiotic elements. Saturos and Menardi then execute their ultimate power: Merging together to form a single, terrifying creature resembling a two-headed dragon. The dragon attempts to overwhelm and annihilate Isaac and his group with their Mars powers, but after an intense scene of combat Isaac ultimately slays the beast in his greatest victory yet. The dragon reverts to the defeated forms of Saturos and Menardi, who fall backward into the Lighthouse's opening and meet their demise.

Isaac's incredible victory intimidates Felix into declaring that he is no match for Isaac now, so that he must now flee to complete Saturos' quest objective while he still can. Suddenly, the Venus Lighthouse experiences a violent earthquake as the structure itself evenly splits up into four quarters, all part of the process that lights the Venus Beacon on its top, causing Sheba to lose her footing and fall off the towering structure, and Felix, beside himself, jumps off the tower after her, to the disbelief of Isaac and his companions. After the Lighthouse reforms and the chaos subsides with the Venus Beacon now brightly alit, Isaac and his friends know that though Saturos and Menardi are gone for good, they need to find Jenna and Kraden, and they assume Felix and Sheba are dead.

In the days to come, Isaac's group conducts a long and tiring search around upper Gondowan, searching for Jenna and Kraden, but they are never found. The Laliverans believe Sheba and Felix have survived, however, because witnesses saw the base of the lighthouse get flooded by the ocean during the earthquake and the sea rising up to catch Sheba safely. Isaac's crew figures that Sheba and Felix are together with Jenna and Kraden and likely Alex as well, all of whom were likely on the peninsula of land named Ijedima that broke off the Gondowan mainland and floated out to sea during the earthquake. Incidentally, Babi Lighthouse was destroyed by this earthquake, meaning that it will not ever be helping Isaac in his goal to discover and enter Lemuria in the future; nonetheless, Iodem entrusts Isaac the Black Orb that allows his group to commandeer the Lemurian Ship Babi moored at Lalivero in the past. With their objectives laid out for them, Isaac, Garet, Ivan, and Mia resolve to sail the Lemurian Ship across Weyard's oceans in search of their multiple goals: To stop Felix and Alex from lighting the Jupiter and Mars Lighthouse beacons and unleashing Alchemy onto Weyard, to rescue Jenna, Sheba, and Kraden from their grasp, and to discover and enter Lemuria in time to retrieve Lemurian Draught and save Babi's life per Isaac's promise.

In Golden Sun: The Lost Age
In contrast to the previous Golden Sun, the story of Golden Sun: The Lost Age is told through Felix's perspective, so Isaac and his group are not encountered in person for much of the game. During Felix's quest Felix can learn what Isaac has been up to recently by talking with townsfolk at certain points in the game.

The Great Eastern Sea
For the next great while, Isaac leads his group and ship on an expedition across the Great Eastern Sea, in search of Felix and their other objectives under his strong conviction and belief that the world would be in terrible danger should he fail his tasks. Isaac will be ready to use force should they ever come across Felix and Alex's group. But until an encounter with Felix somewhere across the seas should come by chance, Isaac explores the sea and its various settlements, hoping to acquire information important to his other objective of entering Lemuria.

It's altogether likely that Isaac makes an attempt at this time to sail into the foggy, craggy Sea of Time where Lemuria is hidden, and the fact there is no Babi Lighthouse to help them keep their bearings in the treacherous sea is one thing that causes Isaac's group to fail in finding Lemuria at first. And even if they did cross the initial ring of stone crags at the perimeter of the Sea of Time, they would have inevitably been turned back by a monstrous demigod named Poseidon prowling the grounds, who is completely invulnerable to the forms of assault Isaac and his friends know.

After stopping to rest at the eastern island chain named Apojii Islands, where Isaac and company get to see Gaia Falls itself up close for the first time in their lives, Isaac sails southward to the continent Indra, and as his crew asks around in the town Madra about Lemuria, Isaac comes to learn about a man who was held in Madra recently, Piers, who possesses a Lemurian ship just like Isaac does and has the ability to perform Mercury Psynergy. Isaac is shocked to learn of a man like Piers, who could very well be a Lemurian, and declares he will follow Piers into the heart of lower Gondowan when he learns that's where Piers was headed. Before leaving, Isaac is told the story of how Piers caused a puddle of water to magically turn into a pillar of ice, and he tells the Madrans that was an example of a power called Psynergy, and he and his friends decide to show the Madrans some of their own Psynergy powers. It is interesting for Isaac and Garet to do this because their hometown of Vale makes it a law not to show Psynergy to outsiders; perhaps it's because somebody else already displayed Psynergy for the town that Isaac felt it was okay.

Isaac is very determined to meet with Piers, believing the Lemurian to be his last chance in entering Lemuria and fulfilling his promise to Babi. He and his companions stop in the southernmost town on Gondowan, Naribwe, and he pays the innkeepers a large sum of coins to pass the message onto Piers the next time they see him that Isaac wants to meet him. Then Isaac attempts to travel northward to Kibombo, but he and his party are presumably ultimately turned back by the Kibombo warriors stationed at the Kibombo Mountains, so Isaac and his group must retreat back out to sea without having met Piers. Isaac's party never does meet Piers throughout the Great Eastern Sea, which makes the eventual next development an inevitability: Babi has finally died in Tolbi, and Isaac was unable to keep his promise despite his best efforts. Needless to say, this failure to save someone's life would weigh heavily on Isaac and his perspective on his own quest, prompting Isaac to be more serious about stopping Felix from activating the Jupiter and Mars Lighthouses than ever before.

Jupiter Lighthouse
Isaac and his cohorts sail through the divide between the continents Gondowan and Indra to make it to the Great Western Sea, where the island continent Atteka is the site of the next Lighthouse they must protect from Felix, Jupiter Lighthouse. They land on Atteka and travel on land in the Lighthouse's direction, passing through the town Contigo along the way. During their stay in Contigo they learn some startling truths about Ivan's past and that he has a sister.

Isaac's party rushes into Jupiter Lighthouse, certain that Felix and his group are in there already and are on the verge of activating the Jupiter Beacon. But then they have an encounter with fate: On one balcony level of the lighthouse's exterior, a trap drops Mia and Garet onto a precariously placed ledge below, injuring Garet's left arm, while Isaac and Ivan left alone on the balcony above. They soon meet the ones responsible for the trap: A pair of Mars Adept warriors Isaac has never seen before, but he judges from their appearances that they are related to Saturos and Menardi, which they are: Karst and Agatio, another pair of powerful warriors hailing from Saturos and Menardi's hometown far up north, which Isaac learns is named Prox. Karst and Agatio seek vengeance towards Isaac because he slew Saturos and Menardi, Karst especially because Menardi was her older sister.

Isaac, strained from his quest and prior events as is, tries to brusquely tell Karst and Agatio off and say he'll save his friends on his own, but the pair launch their assaults toward Isaac and Ivan with the intent to kill. After a desparate battle where Isaac and Ivan put up a surprisingly strong fight to the Mars Adepts with their powers and abilities, Isaac and Ivan are eventually overpowered and defeated, but are still alive to Karst's intrigue, and she and Agatio are about to finish them off when Felix and his party of Jenna, Sheba, Piers, and Kraden step in to stop them. Karst and Agatio interacted and dealt with them previously, but Felix declares his intent to keep Isaac from further harm, and his party forces Karst and Agatio into a deal where Isaac's life is spared if Felix takes the Mars Star Isaac has in his possession, and then activates the Jupiter Lighthouse with the Jupiter Star Felix has. Isaac, lying there on the ground, sees that Felix was willing to save him from death despite their being at odds for their entire quest, and though Isaac does not know why Felix is so set in releasing Alchemy, he places his trust in his former childhood friend and gives up his Mars Star to Felix. Felix and Piers then follow Karst and Agatio up to the top of Jupiter Lighthuose as the other three are left behind to tend to Isaac and his party.

With Garet and Mia saved and Isaac and Ivan patched up, Jenna and Sheba suspect something might be wrong and they check up on Felix. Once Isaac's party fully recuperates, they head up to the aerie of Jupiter Lighthouse, where Felix's party has just been in an intense battle with Karst and Agatio, who have now escaped (with the Mars Star now in their possession, as they have taken it from Felix). Isaac demands an explanation from Felix about everything that has been going on, but everyone is quick to agree that this isn't the best place to discuss all the circumstances, and Felix promises Isaac that they will meet officially in Contigo. Isaac leaves them and Jupiter Lighthouse on this note, sternly warning that Felix can not just sneak off again.

The Reunion
Isaac, Garet, Ivan, and Mia stake out in an empty house in Contigo, awaiting Felix's party of Jenna, Sheba, Mia, and Kraden to meet with them in an appropriate environment, and Isaac is glad Felix kept his promise when his party walks in. In the epic interaction to follow, Felix explains that he was trying to avoid Isaac all this time because he couldn't face Isaac after betraying their hometown Vale by assisting Saturos and Menardi in raiding Sol Sanctum, and that if they met they would have ended up fighting each other, which Jenna in particular could never want. Felix then shocks Isaac with one reason why Felix helped Saturos: Isaac's father Kyle, as well as Felix and Jenna's parents, were not killed in the Mt.Aleph boulder disaster three years ago. In addition to Felix himself, Saturos and Menardi had rescued the parents from death and brought them back to their home colony of Prox where they lived for three years. The people of Prox kept the parents incarcerated at Prox while Saturos would be out on his quest to restore Alchemy to the world, and Saturos promised Felix that he would set his parents free if Felix joined them on their quest.

Felix then tells Isaac another, even more unbelievable reason why he was so set in helping Saturos achieve his goal: It would save the world from eventual collapse. The world of Weyard effectively has its own life force that is literally sustained by the presence of the force of Alchemy, and the absence of Alchemy has been causing the world to actually shrink in size; the perimeter of the world, Gaia Falls, is slowly but steadily growing and consuming further into the flat world, while the continents of the world have been breaking up and beginning to shrink and sink into the waters. It will be eventual, inevitable doom for the entire world if Alchemy is not restored, which is made all the more concerning for Isaac as he and the others believe there is a risk of Alchemy destroying the world anyway, but it's now turning out that Alchemy needs to be restored anyway despite the assumed risk.

Finally understanding why Felix and those he allied with were trying to activate the Elemental Lighthouses, Isaac makes the decision to join forces with Felix's party for the rest of the latter's quest. Then Hama, who Isaac met earlier in his own quest and who is revealed to be the mystery sister to Ivan, comes in to announce that Felix's Lemurian ship now has a pair of magic wings attached to it, allowing the ship to fly. She also brings notice that with three of the Lighthouses now active, the element of the last unlit Lighthouse, Mars, is being suppressed, causing the world to gradually get colder, and the world will freeze if Mars is not activated. And though Karst and Agatio are headed up north to try to activate the Mars Lighthouse for themselves, they will fail because Hama senses that a powerful force does not want to see Mars rekindled. As Isaac's own ship has now vanished (it is presumed Alex stole it for his own use at this point), Isaac's crew joins Felix as they set out together on his flying ship north to Mars Lighthouse to take the Mars Star back and activate Mars themselves.

Mars Lighthouse
Passing into Weyard's Northern Reaches, Felix and Isaac lead their combined group across the bleak, blustery landscape and reach Prox, the hometown of Saturos, Menardi, Karst, and Agatio. Isaac learns from the people and Elder of Prox and their chieftain, Puelle, the history behind the actions of their powerful warriors: The edge of the world up north beyond the Mars Lighthouse is steadily increasing in size and creeping slowly but surely southward to the town's direction. The Proxeans knew this was because of the absence of Alchemy, so they sent their strongest warriors Saturos and Menardi to retrieve the Elemental Stars and activate the Elemental Lighthouses to save the town and eventually the world from utter destruction, meaning to Isaac that the intentions of the Mars Adepts he slew at Venus Lighthouse were noble at their core.

When it is brought to the Proxeans' knowledge that it was Isaac who killed Saturos and Menardi, Isaac jumps and assumes combat stance, but Kraden quickly tells him off and clarifies why things had turned out the way they did, and that Isaac cannot be blamed for pursuing the pair to regain the Elemental Stars they stole. The Proxeans come to forgive him on the basis that Isaac was stronger than they were, which is something he should be prideful of.

Isaac and Felix's group rushes to where Isaac's father and Felix and Jenna's parents are supposed to be kept safe in a house, as Puelle had given the order that the parents should be set free once Felix returns to Prox, but to their dismay their parents are nowhere to be found in Prox. Evidence indicates that the parents went up towards Mars Lighthouse for some reason. Unsure of what could be happening, Isaac and Felix lead their party into Mars Lighthouse, the final lighthouse in their quest.

During their exploration and battles through Mars Lighthouse, Isaac and Felix's forces encounter a pair of lumbering, powerful Flame Dragons, which they dispatch after an extended battle. To their shock, the defeated forms of the dragons transform to become the defeated forms of none other than Karst and Agatio. The Mars Adepts, near death, relate their story of how they were stopped in their tracks and were gauged by "the eye" to lack the will and conviction to go any farther, and were both turned into mindless dragons that were sealed in captivity. Because Karst and Agatio shared Saturos and Menardi's ultimate objective to activate all four Elemental Lighthouses, they entrust the Mars Star to their former "enemies" Isaac and Felix so that Isaac can complete the quest once and for all. Isaac and Felix then lead their group to the aerie of Mars Lighthouse.

At the Mars Lighthouse Aerie, Isaac and Felix's party are suddenly confronted by none other than the Wise One himself. The Wise One, who tasked Isaac to recover the four Elemental Stars, demands to know why Isaac has disobeyed his command, and Isaac and everyone else respond with everything they know about how the world would be destroyed if they don't. The Wise One counters with the scenario that mankind may very well destroy Weyard themselves if mankind can use such power, stating that in time, one man will seek to rule over all with Alchemy's powers, which is an inescapable facet of human nature. The Wise One then reveals a terrible revelation: the entire effort of the Adepts to restore Alchemy has been taken advantage of by the Water Adept, Alex, who is now at Mt. Aleph awaiting the restoration of Alchemy to occur there so that he can gain supreme power for himself. Everyone is thunderstruck; Mia, in particular, feels outright sick with disgust that her own clanmate of the Mercury Clan would employ such a base tactic for self-gain. But Isaac loses none of his resolve in declaring that the beacon must be lit in order to save Prox and Weyard.

The Wise One decides it's time to put the Adepts through the ultimate test by summoning a colossal dragon with three heads to battle them. As the Adepts ready for their final battle, Isaac manages to see the Doom Dragon for what it really is: An amalgamation of the very parents they were trying to find before, including his father Kyle, turned into a single, mindless dragon by the Wise One and forced to battle the Adepts in a cruel ploy that would surely break the Adepts down once the beast is slain and it would revert to the three separate dead forms. Isaac, however, in his greatest demonstration of his virtue, is willing to sacrifice everything he holds dear to his heart and helps his allies slay the dragon in a most epic confrontation, and he remains strong for everyone even as everyone else is horrified and thunderstruck after the battle when they first discover who they really killed. Isaac declares that what they have done was to defy the Wise One to save the entire world; Kyle and the other parents would understand that, and everyone else finds it within themselves to agree with Isaac. With the quest almost at its conclusion, Isaac remains with his father as Felix casts the Mars Star into the Mars Lighthouse's well.

Epilogue
With the Mars Lighthouse now lit, the process that will give shape to the Stone of Sages and herald the return of Alchemy to all of Weyard begins in earnest, with Isaac seeing the beacons of each Lighthouse shoot out their beams of energy and gather over to the southeast of his current position, in the area where his hometown Vale lies. As each Lighthouse is now unleashing immense energy of their respective elements, all of the Adepts present at the aerie of Mars Lighthouse absorb great deals of raw elemental power, Isaac included, but more importantly the bodies of the fallen parents as well, and in a miraculous event attributable to fate the parents are revived by the energy because they were Adepts themselves. Isaac and Felix and their party transport their parents and themselves down out of the Lighthouse and across the now-damaged-by-earthquakes landscape back towards Prox in an evidently lengthy, arduous journey, and the Proxeans nurse the parents back to health.

Meanwhile, at Mt.Aleph, Alex's plot to use his "allies"' quest to restore Alchemy for his own personal gain succeeds, as he is at the top of Mt. Aleph as the beams of the four Lighthouse Beacons merge above Mt. Aleph's airspace to form the Golden Sun, which shoots its combined beam of pure Alchemy downward to enter Mt. Aleph and form the Stone of Sages within - and as Alex stands in the combined beam's path and the beam passes through him, he gains near-limitless life and empowered Psynergy... But then the Wise One appears and reveals to him that Alex's plan was not completely successful; Alex now wields much of the Golden Sun's power, but he has not gained total mastery of reality because the Wise One took the precaution of imbuing the Mars Star with a certain magical property back when they were in Sol Sanctum. This ensured that if someone like Alex tried to take the Golden Sun's power for himself, the last missing portion would now belong to Isaac. Alex is staggered, and before he can react to the concept that Isaac has robbed Alex of his dream, Mt. Aleph begins to sink to the ground as part of the grand process of Alchemy, with Alex presumably being drawn into the earth with the mountain forever.

Isaac (unaware that he gained part of the power of the Golden Sun itself), Felix, and Kraden are personally thanked by the Elder of Prox and Puelle for saving both their town and the entire world, and for effectively bringing about a new, golden age where Alchemy may once again reign supreme. They discuss what might have happened to Vale physically because of all the energy that was released above the town at Mt. Aleph, as well as how they might have to deal with Alex in the future. Isaac is currently most concerned for what is the status of Dora's health after all this time Isaac's been away from home on this incredible journey, but for now everyone will return to Vale, in Kyle and Felix and Jenna's parents' case for the first time in three years.

As the Adepts and the rescued parents leave Prox to board the Lemurian Ship, Isaac asks Kraden and Felix what the meaning of everything that happened at the Mars Lighthouse Aerie was: The Wise One had changed the parents into a dragon that Isaac and the others were forced to fight and pretty much kill, yet the way the parents were revived back by the beacon's light suggests the Wise One would have to have known that. Kraden hazards a guess with wild implications: The Wise One's actions were all part of his grand scheme to test Isaac and his companions as individuals capable of the great responsibility of ensuring that throughout the world, Alchemy is not abused and used for evil.

Finally, Isaac and the Adepts, the three parents, and Kraden return to Vale, but are greeted by a tragic sight: Mt.Aleph and Vale are effectively gone, with the mountain itself mostly submerged into the ground and the entire landscape surrounding it now a giant rocky canyon, with no town or people in sight. Isaac and Garet are awash in disbelief over the apparent truth that Dora and all of Garet's family are gone forever, but this scene doesn't last long: Dora and everyone else believed to have perished show up perfectly fine, revealing that the Wise One warned them to evacuate Vale before the town would be destroyed. Isaac and Kyle embrace Dora together for the first time in three years as everyone else engages in great jubilation, and as Isaac's story ends at last.

=Trivia=
 * When Isaac's party in Golden Sun engages in a battle anywhere and anytime in Venus Lighthouse whether it's the later main portion or the earlier "exit" portion, Isaac will automatically restore 4 PP at the end of each turn because he is a Venus Adept. This is consistent with all Elemental Lighthouses in both Golden Sun and Golden Sun: The Lost Age, which add 4 to the PP recovery values of all Adepts of the same element as the Lighthouse whenever they engage in battles within.
 * Isaac is the main subject of the main optional events that happen in Golden Sun: The Lost Age based on what Isaac and his party achieved in the original Golden Sun and whether that game's completed save data is used for data transfer:
 * Early in Isaac's quest after the eruption of Mt.Aleph, he and Garet join Ivan in taking down the Vault gang of thieves and locking them up in Vault's prison for the crime of larceny during a time of disaster. If Isaac and the other Adepts return to Vault later in the game and speak with the town's mayor, they will learn the thieves broke out of their prison somehow and seek vengeance upon him. Early in Felix's quest in The Lost Age, after Felix meets Karst (seeking vengenace on Isaac herself for his killing her sister Menardi, no less) for the first time in Madra, he will be stopped in his tracks by the bandits as he leaves the town, and they will take out their frustrations about Isaac by attacking Felix's group, but they easily lose. The thieves, threatened by the prospect they might go to jail again, apologize and run away, leaving behind the Golden Boots for Felix to use and equip.
 * During the portion of Isaac's quest that takes place in the Xian region of Angara, a subplot involving the young woman Feizhi and her friend Hsu will play out, with Hsu being trapped in Alpine Crossing by a landslide. Isaac, after having Ivan learn Reveal and before entering the Lamakan Desert, may decide to backtrack to Alpine Crossing and free the injured Hsu from the trapping boulder using the Lift Psynergy. Feizhi is thankful enough to Isaac that after the latter leaves to resume his quest, Feizhi develops a romantic crush on him and decides to make a good-luck charm called the Golden Ring which she'll give to him the next time she sees him. During the Great Eastern Sea portion of The Lost Age, Felix's party would be stopped by Feizhi the first time they enter Champa, and Feizhi mistakes Felix for Isaac because she predicted the Venus Adept coming into Champa and assumed it was Isaac. Feizhi entrusts the Golden Ring to Felix so that Felix may give it to Isaac later (which is an event not explicity depicted in the actual game).
 * During Golden Sun, if Isaac actually wins the this year's Colosso tournament, he will gain a moderate degree of fame as a gladiator and make some vengeful rivals among his fellow Colosso warriors who suspect his victory came from his matches being rigged, rather than some sort of spiritual force named "Psynergy". As such, late in The Lost Age when Isaac's party has joined Felix, the three Colosso Gladiators Isaac beat previously will ambush the party in Shaman Village Cave and demand a rematch, but are easily defeated again by the powerful party of Adepts. The gladiators will apologize to Isaac for their actions and receive Isaac's forgiveness, and they give him the Golden Shirt they found earlier in the cave, and as they leave they suggest maybe they can compete against Isaac again in the next Colosso.
 * Late in Isaac's quest through upper Gondowan, he will have the opportunity to discover and explore the legendary island cave in the Karagol Sea, Crossbone Isle, and he and his party are powerful and capable enough as Adepts by that point to solve all the island's tricks and traps, loot all its treasures, and possible even defeat the terrifyingly powerful ancient ghost pirate protecting the treasure, Deadbeard. Once Isaac's deeds are done, pirates across Weyard will somehow learn of it and Isaac's identity, and recalling the stories that the one who defeats Deadbeard will gain the honorific of leader of all pirates, buccaneers will start seeking out this apparently tough and reliable man to join his pirate crew. If the game file where Deadbeard is defeated is used for data transfer into The Lost Age, then in the town of Alhafra, after the pirate Briggs flees the town on a ship and departs back for Champa, a pair of swashbucklers will appear in the second floor of Alhafra's inn as the town updates. The moment Felix's party comes in, an optional cutscene will occur where the two about Isaac's exploits and state that that means Isaac is their leader now, and that is why they are now looking for him so that they can join his crew. Then they will pass by Felix's group as they leave the inn on their search. It should be noted that this cutscene can occur anytime after when it can first occur, meaning that it can be triggered late in the game when Isaac's party has joined Felix's. In that case, though, the cutscene will play out exactly as it would otherwise, and the pirate pair will not realize they just passed by their new "leader" as they leave the inn in search of him.
 * Isaac is the only character in the Golden Sun series to have made an appearance in another game outside the series, namely as a supportive cameo role in Super Smash Bros. Brawl, and this appearance is his first 3D appearance in a console game and the first time his voice, or the voice of any Golden Sun character for that matter, is heard.

=Quotes=


 * On Jupiter Lighthouse:
 * Isaac: "This doesn't look good... We have to save Garet, and fast!"
 * Agatio: "No, I'm afraid you won't be doing that..."
 * Ivan: "Who are you?"
 * Karst: "Me? Why, I'm Karst."
 * Agatio: "And I'm Agatio."
 * Isaac: "If you're not here to help my friend, then get out of my way, so I can do it myself!"


 * Isaac: "Go on, Felix. Take it. I don’t know why you’re doing this, but I trust you… Take the Mars Star."


 * Isaac: "F, Felix... No! Why are you helping them?"


 * Isaac: (If Felix loses his battle with Karst and Agatio, and after Karst and Agatio leave) "Blast! They must have taken the elevator to escape!"


 * Jenna: "We'll be there, Isaac. I hope you still trust me."
 * Isaac: "I’ve never stopped trusting you, Jenna. I'll be waiting for you in Contigo." (To Felix) "We'll be expecting you. Don't think you can sneak out of this! You owe us an explanation!"


 * During the Reunion at Contigo:
 * Isaac: "Wait for the end of the world to come or wind up accidentally triggering it ourselves… What a choice…"


 * Isaac: (To Felix) "Why did you wait so long to tell me? I would have helped you..."
 * Kraden: "You wouldn't have done it before, Isaac... It would have meant violating the sacred teachings of Vale."


 * Isaac: "Listen, this is Felix's quest now… We're just doing what we can to help out..."


 * In the overworld at Atteka, when flying the Lemurian Ship for the first time:
 * Isaac: "Let's see how far we can take this thing!"


 * In Prox:
 * Isaac: "My name is Isaac."
 * Elder of Prox: "Isaac... Isn't that..."
 * Puelle: "That is the name of the one Agatio said had killed Saturos and Menardi."
 * Kraden: (Isaac jumps back and extends his arm, ready to defend himself with Psynergy) "Isaac, stop that... You are correct, but Isaac had his reasons for fighting them. Saturos and Menardi had invaded Vale, stolen its sacred treasure, triggered a volcano... You cannot blame Isaac for pursuing them and fighting to regain what they had stolen."
 * Isaac: "We only wanted to stop them... We didn't think they'd fight us to the death. They flung themselves into the opening of Venus Lighthouse's beacon..."


 * On Mars Lighthouse:
 * The Wise One: “The people of Prox have committed an unforgivable sin. They must pay the price.”
 * Isaac: “For lighting the lighthouses? Is that their sin? Does that warrant total destruction?”


 * Isaac: (After learning of Alex’s deceit) "None of that matters now. We still have to light the beacon. We don't have any choice. If we don't do it now, Prox will be destroyed! Felix… We have to, right?"


 * Isaac: (After defeating the Doom Dragon) "That's enough… I knew what I was doing the moment I raised my sword. We defied the Wise One in order to save the world. Our parents would understand."


 * Isaac: "Our quest is almost over. I...don't know how I'm going to tell Mom about this... But sorrow can wait. We've got to light the beacon."


 * Epilogue at Prox:
 * Isaac: "We're just glad to have helped save Weyard..."


 * Kraden: "Well, I suppose we should be departing for Vale soon."
 * Isaac: "You're right, Kraden... If we don't, you-know-who might start causing trouble..."


 * Isaac: "I just want to be home again... I want to see how my mother is doing..."
 * Kyle: "Don't worry, Son. I'm sure Dora's doing fine. She's a strong woman."
 * Isaac: "But last time I saw her, she looked so sick, so weak... Even if nothing happened to Vale, I'm still worried..."
 * Kyle: "Don't worry, Isaac. I'm sure she's in wonderful shape. I think she'll be surprised to see me!"


 * Isaac: "It looks like we've got an exciting last trip ahead of us, doesn't it?" (If Felix says yes) "Wow... Setting out like this takes me back to our own quest's start... It was so long ago."


 * Isaac: "If [Vale]'s not there, then what's the point in even going back?"
 * Kraden: "Is that really how you feel, Isaac?"


 * Isaac: "Kraden... Why did the Wise One change our parents into a dragon? Why did he make us fight them? I mean, we almost killed them... He tried to make us kill our own parents. Why?"
 * Kraden: "Do you think that he intended for them to die from the start?" (If Felix says no) "Ah... You don't understand why he put you through all this if he knew they'd survive... We cannot hope to fathom the motives of a being as all-powerful as the Wise One..."
 * Isaac: "You don't know either, Kraden?"
 * Kraden: "I can only hazard a guess... The Wise One... wanted to test you."
 * Isaac: "What do you mean, test us?"
 * Kraden: "I cannot tell you more... It is up to you to find the answer. Will we use Alchemy to wage war, to raise armies? Or will we use it to grow wise, to rise above our petty feuds and perform great deeds? You were willing to sacrifice everything for this quest. I'd say you've risen to this challenge."

In fan circles
Isaac is obviously one of the main characters and points of interest in the Golden Sun fan fiction community, with Isaac most often depicted in a Mudshipping scenario that romantically involves him with Mia. Another ship that is growing in popularity is Valeshipping, which depicts him with Jenna, and both are from Vale. Although it is still small there seems to be a growing movement pairing Isaac with Ivan.

Portions of the fanbase disagree with the personality Isaac was given for his speaking role in The Lost Age because he seems curt and abrasive from when he first appears at Jupiter Lighthouse, and his nature as a silent protagonist in the first Golden Sun prompts players to come up with their own interpretation of Isaac (as is the essential purpose of being a silent protagonist), which likely wouldn't match how Isaac actually is in the second game. It should be noted that Isaac's attitude in The Lost Age would be consistent with what has been going on in his side of the story prior to this appearance, however, for in his side he had tried his hardest to enter Lemuria and save Babi's life like he originally promised Babi in Golden Sun, but eventually failed.