|Hair color||Reddish pink|
|Japanese name||Karst (カースト Kāsuto)|
Karst is a Mars Adept who along with her partner Agatio is a main antagonist in Golden Sun: The Lost Age. The pair nominally follows in the footsteps of the original game's Saturos and Menardi and shares their goal of lighting the four Elemental Lighthouses and restoring Alchemy to the world, but seek vengeance upon Isaac in response to the murder of Saturos and Menardi at his hands at the end of Golden Sun. Of the two, Karst is the more personal side, for Menardi was her sister.
Karst hails from the northernmost settlement on the world map, the town of Prox, and lived with her sister Menardi; though they are sisters, they look nothing alike. Karst and the other people of Prox are of a humanlike race that is distinctively characterized by almost reptilian scales and spikes on various areas of their flesh - but more importantly, their natural proficiency to the Mars element. They are thus afforded both a natural toughness and a natural immunity to the constant cold of their environment. While Karst appears to be a powerful warrior in her own right, Agatio appears to have the higher authority of the two because his strength and power is claimed to approach that of Saturos'.
At the start of the first Golden Sun, she and Agatio remain in Prox as Menardi and Saturos and their recently discovered companions Alex and Felix depart from Prox to set out on their quest to restore the force of Alchemy to the world, thereby stopping the continued growth of the abyss at the end of the world that threatens to consume Prox in the future. Felix's parents and Kyle, whom Saturos and Menardi rescued from death previously, also remain behind at Prox, and are essentially kept incarcerated there on Saturos' order so that Felix is coerced into willingly assisting Saturos on his quest; only once the four Lighthouses are lit, subsequently restoring Alchemy to the world, will the parents be freed.
 In Golden Sun: The Lost Age
For the most part, Karst functions together with Agatio as a single character unit in terms of plot. She seeks out Isaac throughout the game with the intent to "repay" him for his murder of her sister, Menardi.
 The Great Eastern Sea
At any point in time in between Menardi's activation of Venus Lighthouse and the later tidal wave, Karst and Agatio depart from Prox and sail down across the Great Western Sea, then cross over into the Great Eastern Sea; whether they depart from Prox on their own volition or by consent of Prox's ruling body is not specified. The tidal wave that originates from the Sea of Time later transpires, which physically shifts the continent of Indra southwest so that it is sandwiched between lower Gondowan and northwestern Osenia, effectively corking the sea route Karst and Agatio just took to reach the Eastern Sea. The pair are now unable to return to the Western Sea, which might be an issue in the future in regards to reaching and activating the remaining two Lighthouses, which are located in the Western Sea.
Presumably, for a while after the start of The Lost Age, Karst and Agatio search the Western Sea for Saturos and Menardi. They eventually moor their ship somewhere on Indra and split up in their search for information about their companions' whereabouts. While Agatio heads into lower Gondowan to go to the small town of Naribwe, Karst goes to the town of Madra and waits idly, whereupon she hears rumors of a traveler named Isaac that had just passed through the town earlier. It is there that she is happened upon by Felix and his traveling party for the first time since Felix's stay in Prox. Karst demands to know where her sister Menardi is, but however hesitant to respond Felix's group might be, Karst discerns the incredible truth that Menardi, for all her power, was killed by Isaac. Karst begins to become consumed by a drive to avenge her sister's death, and expresses her intention to seek out and kill Isaac. Karst tells Felix that he will have to find a way back to the Western Sea and light Jupiter Lighthouse on his own while she takes care of this personal matter, then storms off back to the ship.
Karst and Agatio, just before they depart back out to sea, are approached by Alex, the other man that accompanied Saturos and Menardi on their original quest. He convinces them to let him join them on his ship by providing them important information and insight, such as about how the Mars Star is currently in the possession of Isaac's group rather than Felix's. Alex directs them to the seaside town of Champa and wait for Felix's party to arrive there (he predicts Felix's group will come there, which strikes Agatio as remarkable foresight). Once Felix arrives, Alex lets Karst and Agatio give a more thorough introduction of themselves to Felix's party and intimidate them into prioritizing the return to the Great Western Sea and the reaching of Jupiter Lighthouse. Karst and Agatio are told by Alex, however, that he doesn't consider himself specifically on "their side" through all this, for his only concern is the eventual activation of all four Lighthouses. Karst also takes offense when Alex states that he thinks she and Agatio, like Saturos and Menardi, are pretty much akin to simple brutes that can't be expected to be handle the task that Felix is currently set on, which is why he means to leave the task to Felix. After everyone has said their piece, Karst and Agatio leave with Alex to let Felix resume his journey, and from then on Karst and the other two presumably follow Felix's ship across the ocean at a safe distance, always keeping a close watch on Felix's activities.
 Jupiter Lighthouse
After a great period of time, Felix's party has gained the Psynergy ability necessary to remove the rocky obstacles that were created when Indra collided with lower Gondowan, thus allowing their ship passage into the Great Western Sea. Karst, Agatio, and Alex soon follow, and soon land on the continent of Atteka and follow Felix's footsteps into Jupiter Lighthouse. Karst's group apparently become aware that Isaac's group has entered Jupiter Lighthouse as well. Karst and Agatio discover and study an ancient trap mechanism, and find they can use it to divide Isaac's party up so that they can attack and destroy them while separated. They know that among Isaac's party is a Mercury Adept named Mia, who technically could be the most dangerous opponent to Mars Adepts like them, so as they lay in wait and Isaac's party comes around, they specifically aim for Mia when they time the trap. Mia falls down to a ledge below; Karst and Agatio are pleasantly surprised, though, that the Mars Adept Garet fell in with her.
Karst and Agatio present themselves to Isaac and his remaining companion, the Jupiter Adept Ivan, and proclaim that it is now time for Isaac to pay for his deed of the murder of Menardi. They also describe how the seal placed on Alchemy is responsible for the dire circumstances currently beset upon their hometown of Prox, and by this point they have apparently been consumed by an obsession: They proclaim that once Alchemy is released, Prox will recover its lost power as a nation, and then all the people of Weyard will kneel before it. Obviously this is not something Isaac's side agrees with, but when they ready themselves for a two-on-two "fair fight", Karst clarifies that they brought a third Adept to help them kill Isaac's party, Alex. Just then, Karst notices that Alex has completely abandoned the Mars Adepts and is nowhere to be seen; considering this a betrayal, she and Agatio note they'll do the same to him after they've taken care of Isaac's party, and so they attack Isaac and Ivan with the intent to kill.
Even though Karst's most personal grudge is against Isaac, she takes on Ivan individually while letting Agatio, the stronger of the pair, take on Isaac, the strongest of his party. Isaac and Ivan fight desperately but ultimately end up thoroughly defeated. Briefly expressing surprise over the power of their opponents, Karst and Agatio are about to kill them when just then, who else should show up but Felix and his party to prevent them from the deed. Felix's side declares their full intention to betray and fight Karst for the sake of protecting Isaac. Weakened from the battle, Karst admits they have no choice but to let Felix's side do what they will with Isaac, provided Felix takes the Mars Star from Isaac and then comes up with them to the aerie of Jupiter Lighthouse to light it with the Jupiter Star. She says, after all, that for all the rage she feels over Isaac's murder of her sister, she is not blinded it. Felix agrees and comes up to the tower's top to light the Jupiter Beacon atop Jupiter Lighthouse.
Once Felix lights Jupiter Lighthouse, Karst and Agatio then break it to him that they simply can't trust him anymore, and that now that the Jupiter Beacon is alight, they have no further need for traitors. Since the last lighthouse, Mars Lighthouse, is up north near Prox, the Mars Adepts presume they can light it themselves, so Karst steals the Mars Star from Felix. Karst and Agatio taunt Felix by assuring that Prox would release Felix's parents once all four Lighthouses are lit, but if Felix is dead, they'd probably have to spend the rest of their lives in Prox anyway. Karst and Agatio proceed to attack and attempt to finish off Felix once and for all, but the other members of Felix's party quickly arrive from below to assist him in his battle against the pair, and soon the pair find themselves fighting against four Adepts at once.
At this point in The Lost Age, the battle can go either way: either Felix's party may emerge the victor, or Karst and Agatio may defeat them in battle and leave them unconscious. In the scenario that Karst and Agatio win, Karst comments that everyone they've battled thus far have all been far more powerful than they expected. When Agatio suggests that Isaac's party might be coming and that they should leave, Karst insists that treason deserves death and that Felix's party must be finished. At that moment, Alex reappears, telling them that there is no time for petty grudges. Karst takes the opportunity to recite the same death threat at Alex for his betrayal earlier, but Alex illustrates that they have been thoroughly drained from their battles with both Isaac and Felix so they are in no condition to fight him too. And since Isaac and his rejuvenated party are coming up at this very moment, and since Karst has the Mars Star they need to complete their more important task, Alex convinces the pair to flee Jupiter Lighthouse with him while they can, using the now-functional elevator system. They leave just as Isaac's group comes upon Felix's party.
In the scenario that Felix's party outlasts their opponents and renders them helpless on the ground, Agatio tells them to finish the job. Karst immediately presents a hypothesis intended to put emotional pressure on Felix: What if the people of Prox decide to kill Felix's parents if neither Karst and Agatio nor Saturos and Menardi return to Prox, having been killed in action by the very people whose parents are currently being held in Prox? Jenna asserts she doesn't believe the people of Prox would kill them (and she is frankly right). Before Felix can decide what to do with the pair, Alex chooses this moment to reappear, and quickly revives and heals Karst and Agatio enough so that they can stand, albeit barely. Alex reasons that if Felix is not going to finish them off, then the pair'd be better off not being left there at the lighthouse's aerie, so he will be escorting them out away from the lighthouse. Karst is annoyed and expresses disdain over the fact Alex apparently isn't going to help them defeat Felix's group in battle, but Alex quickly points out that Isaac's party is currently coming up so they should flee while they can. So, the Mars Adepts and Alex take the elevator down just as Isaac's group and Felix's group have their encounter.
 Mars Lighthouse
Following the episode at Jupiter Lighthouse, Karst and Agatio part ways with Alex; it would stand to reason that they're all too happy to do so based on prior events. The pair, with the Mars Star in hand, sail back up north to their hometown, Prox (somehow bypassing the glaciers and walls of ice that have blockaded the natural sea route to the Northern Reaches). They briefly stay there and relate to the villagers the events of their expedition and, still clearly resentful of Felix, tell them about how Felix "ran away because their quest was too dangerous". Karst and Agatio soon officially depart north to Mars Lighthouse, with the intent to light it and finish Menardi and Saturos' original objective.
As Karst and Agatio explore the frozen structure, all of a sudden they are beset upon by The Wise One, the single-eyed entity and guardian of the seal placed on Alchemy. It looks into the pair's souls and declares they lack the will to go any farther. The Wise One then uses its powers to transform Karst and Agatio into a pair of lumbering, mindless Flame Dragons, and encases them in a slab of ice at the bottommost level of Mars Lighthouse. The two remain in this state of suspended animation for a period of time until Felix and Isaac, who have since merged forces into one full party of Adepts, enter and explore Mars Lighthouse themselves. The Adepts eventually come to the bottommost chamber and free the creatures. The two dragons immediately attack the party on instinct, using many of the same Psynergy abilities Karst and Agatio demonstrated on Jupiter Lighthouse. After an extended battle, the Adepts eventually defeat each beast.
The two Flame Dragons revert back to the forms of Karst and Agatio, thoroughly beaten and near-death, to the Adepts' likely considerable surprise. As the pair relate what little they can remember of "the eye" they came across, they realize that they are starting to feel cold, something the people of Prox should be immune to, meaning they are nearing death. They then notice that Felix and the others are in the room with them, and in a sort of last-minute change of heart they beg him to take the Mars Star and light Mars Beacon himself, in spite of their prior antagonism. Felix and the others take the Mars Star and head up to the Lighthouse's aerie, having no choice but to leave Karst and Agatio behind. The last thing the Mars Adepts are heard saying is that they swear to keep alive at least until they can tell the beacon has been lit; whether they achieve this is up to the player's interpretation.
Karst and Agatio do not figure into the finale of The Lost Age beyond having given Felix back the Mars Star. In the dramatic finale, the Mars Lighthouse eventually is activated through the efforts of Felix and Isaac's group of Adepts. With the establishment of the four Elemental Beacons, Alchemy is restored to the world, and Prox is saved from eventual destruction. The people of Prox congratulate and thank Isaac and Felix for what they have done, even though they feel sad that Saturos, Menardi, Karst, and Agatio had all lost their lives. In a piece of Mind-Readable dialogue in Prox accessible only by hacking, it is indicated that the people of Prox were told by Felix's group that Karst and Agatio "were defeated by a monstrous dragon" which Felix and the others then beat and slew. It is likely this was told by Felix's group as a white lie to the Proxian people to avoid creating further resentment between Prox and the people of Weyard, since technically it was Isaac and Felix's group that killed the pair much like how Isaac killed Saturos and Menardi beforehand.
 As a boss
The scripted battle with Karst and Agatio occurs at the top of Jupiter Lighthouse after you decide to cast the Jupiter Star into the lighthouse's open well. Several things make this boss counter unique: You begin the battle with your party only comprising Felix and Piers. Survive two turns of the battle and then a brief cutscene shows Jenna arriving to join your party in the battle, and then after another two turns another similar cutscene occurs with Sheba arriving to join the battle. From that point on, the boss battle plays out as the only boss battle in either game that can be optionally won or lost; the plot still progresses if you lose, and whether you win or lose only affects the cutscene following the battle and whether you get the EXP and material rewards.
Karst has 3186 HP, 320PP, 354 Attack, 107 Defense, 235 Agility, and 50 Luck. In terms of resistance, she has a Mars Resistance rating of 175, a Venus Resistance rating of 127, a Jupiter Resistance rating of 100, and a Mercury Resistance rating of 72, and in regards to her abilities she uses her available Mars-based attacks with a power rating of 105 and her available Venus-based attacks with a Venus power rating of 100. Her battle commands are as follows:
- Death Scythe: Used 53 out of 256 times, this is an enemy ability where Karst comes forward, charges an attack, and strikes, while a holographic image of a Grim Reaper slashes the target with its scythe in tandem. This deals a Venus-based attack equal to her normal physical attack with an additional 35 damage points, unless the potential added effect of instantly downing the target kicks in. (This is actually the exact same ability as Menardi's "Death Size", but with its name fixed.)
- Fiery Blast: Used 47 out of 256 times, this is a Psynergy spell where a large explosion of fire, spreading many embers, discharges at the opposing party's position, dealing a Mars-based attack with a power rating of 110 and a range of 5 targets. It costs Karst 19 PP to use.
- Djinnfest: Used 41 out of 256 times, this is an enemy ability where Karst projects a flurry of large glowing musical note symbols at the party, putting one of each member's active Djinn in Recovery mode. This acts with increased priority.
- Supernova: Used 35 out of 256 times, this is a Psynergy spell where a large and extended explosion of fire discharges at the enemy party's position as the camera swivels, dealing a Mars-based attack with a power rating of 170 and a range of 7 targets. It costs Karst 31 PP to use.
- Healing Aura: Used 29 out of 256 times, this is a Psynergy spell that restores her and Agatio's HP by just over 100. Costs 11 PP.
- Break: Used 23 out of 256 times, this is a Psynergy spell that removes all buffing effects that the party members had applied to themselves with Psynergy and other effects at this point. Costs 5 PP.
- Heat Kiss: Used 17 out of 256 times, this is an enemy ability where Karst projects a flurry of orange clouds shaped like valentine hearts against the party, having a chance to lower the Attack rating of up to 3 Adepts by 25%.
- Attack: Used 11 out of 256 times, this is Karst's standard physical attack.
In general, Karst does not do quite as heavy damage as Agatio is capable of, but she might be considered the more dangerous opponent regardless because of her potential instant-death skill she shares with Menardi from the previous game. It depends on the player which of the two opponents should be focused on first, but always focus on piling on the damage of one opponent over the other because they are most dangerous when fought together simultaneously. Either one can be easily handled and dispatched individually.
If the battle ends up won for your party, then Karst yields 2813 EXP and 5280 coins, which adds up with Agatio's 3000 EXP and 3740 coins to form 5813 EXP and 9020 coins. Karst is also guaranteed to drop a Dark Matter.
- Karst, along with Agatio, while waiting on top of Jupiter Lighthouse for Felix and Piers to light the Jupiter beacon with the Jupiter Star, has a hidden line of Mind Read-able text that normally cannot be seen because Sheba, the only Adept in your party that can use Mind Read, is out of your group at the time. Using a hacking device to allow Felix or Piers in your party to use Mind Read, Karst is revealed to be thinking "Once Jupiter is lit, we'll have no need for you. Just watch..."
- Like Saturos, Menardi and Agatio, Karst is featured in Dark Dawn as a poster that must be burnt to complete an obstacle course.
- At Madra:
- Sheba: "You won't see Menardi or Saturos again. Isaac killed them. They're probably at the bottom of the sea by now..."
- Jenna: "Sheba! Quiet!"
- Karst: "Hmph! I heard that, you wretched little thing! Can it be true? Is my sister dead?" (If Felix says no) "No? Then where is she!? Show me my sister! What is the matter? Is it so very hard? You were traveling with her--bring her to me! She would never have left you behind... and yet you are alone... So it's true? She's... Who is this Isaac?" (Everyone keeps quiet) "What? You feign ignorance? Why? Would you protect him from my fury!?"
- Kraden: "How do you know it wasn't Felix who defeated your sister?"
- Karst: "What do you take me for? I'm a warrior, like my sister...I can gauge a man's strength at a single glance. Even if you doubled Felix's power, he would still be no match for my sister."
- Karst: "We have our own work to do, and number one on the list is taking care of Isaac! Are we clear on this, Felix?" (If Felix says yes) "Aren't you an obedient boy..."
- Karst: "We're going to find that Isaac... I'm going to find this Isaac... And I swear that the last thing he sees will be Karst avenging the death of her dear sister!" (Karst storms off and leaves town)
- Sheba: "Wow. And I thought Saturos and Menardi had issues."
- At Champa:
- Sheba: "Karst!"
- Karst: "That's right, Karst! I'm flattered that you remember!"
- Karst: "Enough of your childish gibes! Alex, I want to know what makes these punks useful!"
- Karst: "But we will always be nearby... pushing you to make your way to Jupiter Lighthouse swiftly."
- At Jupiter Lighthouse:
- Agatio: "We shall bring Prox back from the edge, and then all the people of Weyard will kneel before us!"
- Ivan: "You think we'd let you, after hearing all that nonsense?"
- Karst: "See! You're a hindrance!"
- Isaac: "So that's the deal, is it? You came up here to fight us?"
- Karst: "Oh, did you figure that out all on your own? Impressive! I'm quite fond of intelligent boys..."
- Karst: "Oh, great... Are you going to betray us now?" (If Felix says yes) "Typical. And you're going to try to stop us from finishing them off, aren't you?"
- Karst: "Agatio, if we fight Felix now... we'll be destroyed."
- Agatio: "Isaac killed your sister! Where is your anger!?"
- Karst: "I am filled with rage, but not so much as to be blinded by it."
- Agatio: "We've got the Mars Star! We don't need you anymore!"
- Karst: "You know what that means, of course, don't you?" (If Felix says no) "No? Well, how can I put this? It's time to die!"
- Piers: "But what will happen to Felix's parents?"
- Agatio: "We keep our promises! Once all four lighthouses have been lit, we shall release them!"
- Karst: "We would never do anything as terrible as breaking our word... as you have done so casually."
- Agatio: "But if you're dead... Who will come to take them home from Prox?"
- Karst: "I guess they'll just have to spend their remaining years in the frozen wastelands of the north!"
- Alex: (If Felix wins the battle against Karst and Agatio) "If you're not going to finish them off, you'll just be leaving them here, won't you?"
- Agatio: "You're not going to help us defeat these brats?"
- Karst: "You better not be expecting a big thank-you for this, Alex!"
- Alex: "Of course not, Karst. I would never ask for your gratitude."
- Agatio: (If Felix loses the battle against Karst and Agatio) "If we stay here much longer, Isaac and the others will come! We should leave!"
- Karst: "I know... But treason deserves death! We must finish them!"
- Alex: "There's no time for petty grudges!"
- Agatio: "Alex! You..."
- Alex: "You no longer consider me a friend? I do not care."
- Karst: "It goes beyond that, Alex! You've betrayed us, and treason deserves death!"
- Alex: "Yes, I heard you the first time."
- At Mars Lighthouse, following the battle with two Flame Dragons that turn out to have been Karst and Agatio:
- Karst: "Why am I so cold? We of the Fire Clan are meant to be immune to the cold..."
- Agatio: "I feel the cold too, Karst... I... I'm afraid we're going to die up here..."
- Karst: "I can feel it now... The long, dark sleep creeping into my soul..."
- Karst: (To Felix) "We can't even stand... We're in no condition to go on. Light the beacon for us... Please."
- Agatio: "You'll need the Mars Star. Go on... Take it."
- Karst: "Please hurry... If I can just see the light of the beacon, I'll know that I haven't died in vain."
- Karst: "Your hands... so warm... People have such warm hands... I had forgotten..."
- In Prox:
- Villager: "It's too bad about Agatio and Karst... They weren't bad people... A little obsessed, yeah, but it's still sad that they're gone."
 In fan circles
Karst, compared to Agatio, is a popular character for her element of vengeance and personal vendetta in response to how Isaac killed her sister Menardi; she is the more personal side to The Lost Age's "antagonistic" unit whereas Agatio is the more brawny. There is, of course, a shipping genre for Karst and Agatio ("Dragonshipping") much like how there was one for the previous game's pair Saturos and Menardi. However, because she has several important interactions with Felix throughout the game and is implied to have had a relationship of some sort with him during his three years in Prox, "Duskshipping" (fan fiction centering on Felix and Karst) is by far the most popular shipping genre for Karst.
When not romantically paired with each other, Karst and Agatio are usually depicted as old friends; it is rare that her relationship with Agatio is interpreted as being strictly professional.
Deathfic focusing on Karst meeting her end within Mars Lighthouse is relatively common, though some fans speculate that the lighting of Mars Lighthouse would have saved her and Agatio in the same way that it saved Felix and Isaac's parents.
|Bosses in Golden Sun|
|Vault Bandits • Tret • Saturos • Killer Ape • Hydros Statue • Manticore • Kraken • Azart • Satrage • Navampa • Toadonpa • Storm Lizard • Tempest Lizard • Saturos and Menardi • Final boss • Deadbeard|
|Bosses in Golden Sun: The Lost Age|
|Chestbeaters • King Scorpion • Briggs and Sea Fighters • Aqua Hydra • Serpent • Avimander • Poseidon • Moapa and Knights • Karst and Agatio • Flame Dragons • Final boss • Valukar • Sentinel • Star Magician • Dullahan|
|Bosses in Golden Sun: Dark Dawn|
|Tangle Bloom • Dim Dragon • Dim Dragon Plus • Stealthy Scouts • Sand Prince • Ku-Tsung and Ku-Embra • Ice Queen • Sludge • Mountain Roc • Blados and Chalis • Blados, Chaos Hound, and Chalis • Final boss • Ogre Titans • Ancient Devil • Star Magician • Dullahan|
|GBA||Isaac Garet Ivan Mia | Felix Jenna Sheba Piers|
|DS||Matthew Karis Tyrell Rief Amiti Sveta Eoleo Himi|
|GBA|| Kyle Dora Saturos Menardi Alex The Wise One Kraden |
Babi Hammet Tret Hama Feizhi Dodonpa Briggs Karst
Agatio Susa Hydros Moapa Puelle
|DS|| Nowell Blados Chalis Arcanus Bogho Baghi Paithos |
King Wo Ryu Kou Hou Zan Laurel Vande Volechek
High Empyror Unan