Karst

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.

Biography
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 in Golden Sun: The Lost Age
Karst makes an appearance as one of two boss enemies fought simultaneously at the end of the Jupiter Lighthouse dungeon, with the other being Agatio.

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 Dark Matter rewards.

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.

Karst is especially likely to be affected by Defense-lowering effects. Her statistics are as follows:

Karst uses the following battle commands with :

Trivia

 * 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.

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.