At last, the power of nature is mine to control as I will!
~ Alex believing himself to be an immortal now

Alex (in Japanese: アレクス, Arekusu), also known as Arcanus, is a Mercury Adept and is generally considered to be main antagonist in the Golden Sun series, despite him helping you at certain points. Whether this is for his own benefit or because he truly desires to help is uncertain. One thing is certain however, and that is how he will stop at nothing to achieve his own personal goals, and they come before anyone else. 


Alex is a mysterious Mercury Adept hailing from the wintry town of Imil, and alongside his cousin, Mia, are the last living remnants of the Mercury Clan by the time of the original Golden Sun. By the time the events of the game are set into motion, his power is already beyond that of any adept in the world, wielding immense power. It is unknown how he learned this, but it is suggested that he ran away from his hometown at an early age to discover these new abilities. He has terrifying capabilities and learns a vast array of unusual powers, such as being to instantly warp to a nearby point at will, or being able to revive people from near death without batting an eye. However, Alex desires more than just his current power. It is presumed Alex learned of the tales of Alchemy, and with mastery over it, would activate the four Elemental Lighthouses and bestow the wielder unlimited power, possibly to dominate the world. To this end, Alex manipulates all parties, both villainous and the Heroes of Vale to his ultimate goal of complete domination, while remaining a complete mystery to all who behold him.

In the Golden Sun series

In Golden Sun

Before the main plot, Alex is approached by the Mars Adepts Saturos and Menardi, who are conducting research on the fabled Elemental Lighthouses. The two aimed to break Alchemy's seal by activating the Lighthouses with the corresponding Elemental Stars. Having failed to breach Mt. Aleph before, Saturos and Menardi have Alex join them in a second planned raid, needing Alex's Adept powers to breach Mt. Aleph. Alex joins them, abandoning Mia and leaving Imil with Saturos and Menardi.

Alex remained in the company of the two Adepts as they recruited Felix for their purpose, staying relatively loyal to the two as they quested through Wyard. At the Sol Sanctum, he forces Garet to hand over the Elemental Stars, afterwards sailing to the continent of Gondowan. Alex and the other finally reach Vale near the foot of Mt. Aleph, commencing their raid of Mt. Aleph. They stumble across Kraden and his disciples doing an investigation of the Elemental Star chamber, and so Saturos and Menardi take Jenna and Kraden hostage. Alex retrieves three of the Elemental Stars from the group, and flee. Isaac, a hero meant to oppose them, elsewhere removes the Mars Star and awakens the Wise One. To preserve the operations, Alex's group flees without the Mars Star, but not before he convinces Saturos and Menardi to take Jenna and Kraden as captives.

With the Stars they have, Alex and his group now seek to infiltrate the Mercury Lighthouse. As they travel, Alex intentionally avoids his hometown as the rest of his associates pass through. Once they reach the Mercury Lighthouse, Alex uses his Psynergy to allow them access, and activate the Lighthouse with its respective Star. Mia arrives on the scene, and Alex casually makes himself known to the Adepts. Mia is mortified at Alex betraying his bloodline oath, but Alex tries to subtly convince that the potential power of the Lighthouses should not stay dormant. He then warps away with Saturos, rejoining wiht the other members and making their way to the other lighthouses. Mia joins Isaac as he pursues Alex and the others.

As soon as they light the next Beacon of the Lighthouse, Saturos, Menardi, and Alex are confronted by Isaac, Mia and their group. Alex hides away as Saturos does battle with them, and is surprised when Saturos ultimately ends up defeated. Saturos's groups retreats with Alex, causing problems all across Angara to impede Isaac's progress. Alex personally helps his group travel through the Sulhalla desert with his Synergy. Near the exit of the Sulhalla Desert, Alex's group finds a Jupiter Adept named Sheba, and force her into their group because of this. Passing through the next town, Alex and the group arrives at the next Lighthouse as Alex cryptically claims his group doesn't know much about the mysteries of the Lighthouses.

Alex, Jenna and Kraden are next ambushed by Tolbian soldiers who seek to rescue Sheba. Alex employs his Synergy and defeats them effortlessly, following those who flee. Saturos and Alex's group finally reach the last tower. Saturos, Menardi, and Sheba try to go up on their own, but Felix directly confronts Saturos and Menardi over Sheba's needless involvement. Alex is secretly impressed, when Isaac and his group show up to confront Saturos again. Jenna attempts to stop the fight, but Alex stops her, saying that Saturos and Menardi can deal with them on their own. Saturos and Menardi meet their end and fall into the well of the Lighthouse, while Alex, Jenna and Kraden are marooned by an earthquake caused by the Lighthouse.

In The Lost Age

After some time, Alex informs Jenna and Kraden that Felix and Sheba have washed up on the buoyant island's beach, alive but unconscious. When the two come to, they reveal to Alex, Jenna, and Kraden, that Saturos and Menardi have died and that Sheba and Felix fell into the ocean. The five now in an uneasy relationship, Alex now has to contend with getting off the island and finishing Saturos's quest. He then decides that restoring Alchemy would be better if he did it alone, going to Daila and then Madra. He meets up with Felix's party, reporting that there are no ships in Daila. When Felix offers to join him, Alex immediately refuses.

The island is soon besieged by a massive Tidal Wave, knocking everyone unconscious. When the rest come to, they realize Alex has left to explore Indra on his own and get a ship. Alex travels south on his way to Madra. He gets sidetracked when he sees Piers being taken captive by Madrans. Alex secretly watches, while Piers reveals to the Madrans that he is a Mercury Adept.

As Felix comes to Alhafra to look for a ship and confronts Briggs over Pier's imprisonment, they meet with Alex yet again. Alex suggests they fix the ship while they are at it. After Felix's run-in goes well, Alex teases him, mentioning that Mia would have done similar. Alex learns that Madra's ships were destroyed by the tidal waves, but learns  that Alhafra has just finished construction on a new ship. Going to Alhafra, he learns in dismay that the ship was too damaged by the tidal wave. Alex then lodges at the inn in tire.

After Felix's party leaves, Alex does the same. He wonders about borrowing Piers' ship for himself. Before he can do so, Felix and Piers return, having taken the Black Orb to control the ship. Alex withdraws, but later meets Karst and Agaito. He learns that the two seek to avenge Saturos and Menardi, and decides to join them on their own ship. They set sail, with their current objective the Jupiter Star needed to activate Jupiter Lighthouse which is currently in the possession of Felix's traveling party. Alex decides, however, that Felix and his group are far stronger and more capable than what he originally gave them credit for. Alex sees Agaito and Karst as no more promising than the deceased two he used to work with, and decides to leave the task of the Jupiter Star to Felix.

Following Champa, Alex, Karst, and Agatio follow Felix's traveling party wherever they go across the Great Eastern Sea on Felix's journeys, with the intention to make sure that Felix does not stray unnecessarily from his core quest. Despite their previous threats, Alex and his group do not physically encounter Felix's group again until long after Felix has made it into the Great Western Sea, when he has reached Jupiter Lighthouse and has started to explore and climb it. Alex foresees that Felix's party will be headed to the cliff-side town of Champa, and he and Karst and Agatio go there and lie in wait until Felix's party arrives. Alex first remarks about how he sees Felix has "replaced" him with Piers as their new water Adept, and admits he was once going to "borrow" Piers's ship. Then he lets Karst and Agatio threaten Felix by saying that if Felix does not hurry up on his objective to reach and light Jupiter Lighthouse, they will take the Jupiter Star themselves and perform the task themselves.

Alex does not have any moral qualms, however, about letting everyone know that he does not consider any of them terribly useful or intelligent, and that includes Karst and Agatio and the deceased Saturos and Menardi. He clarifies that he is "on no one's side" through all of this; his only concern is to see all four Lighthouses lit once again, and Felix's group is the most capable of this responsibility. Alex and the Mars Adepts promise Felix that they will always be near Felix's group to push and pressure their way to Jupiter Lighthouse.

Alex, Karst, and Agatio enter the Jupiter Lighthouse in pursuit of Felix, tailed now by Isaac's party. Karst and Agatio split Isaac's group, and then personally confront Isaac's group with the intent to kill them; the Mars Adepts immediately realize, however, that Alex has taken the opportunity and deserted them. Alex materializes before Felix and speaks what's on his mind: He knows Felix will not emotionally handle Isaac's death enough to light Jupiter Lighthouse. Thus, Alex personally heals Felix's party before sending them off to save their friends.

Much confrontation occurs between Felix's party and Karst and Agatio before Felix eventually achieve the lighting of the Jupiter Beacon, as Alex believed he would. Before anything else happens, Felix's group breaks out into a last fight with Agaito and Karst, but they are interrupted by Alex himself, reporting that Isaac's party has recuperated and is coming up in their direction. Karst and Agatio are too drained from their battle with Felix to fight Isaac off too, and they already have possession of the Mars Star that they would need to light Mars Lighthouse themselves; Alex uses these facts as his argument to convince the Mars Adepts to flee Jupiter Lighthouse with him while they can. Thus do Alex and the Mars Adepts leave Jupiter Lighthouse, right as Isaac's party arrives to the aerie.

After the events at Jupiter Lighthouse, Alex and the twosome part ways. Alex immediately prepares for and enacts the final phase of his master plan, sailing from Atteka to Angara with all haste to get to Mt. Aleph. He lands on Angara and begins his final travel towards Vale, where he then scales Mt. Aleph. No sooner than when Alex reaches Mt. Aleph's very peak does the Mars Lighthouse get activated and the global process that heralds the return of Alchemy to Weyard commences. The four Lighthouse Beacons shoot out their beams of purified energy into the airspace above Mt.Aleph, which merge together to form a golden sphere of the power of Alchemy named the Golden Sun. In turn, it shoots down into Mt.Aleph to give shape to Stone of Sages within the mountain. As Alex stands in the beam's path and its power passes through his body, he is infused with immense power and near-limitless life, giving him god-like power which he had always sought.

Alex is bewildered because he thinks he should be all-powerful, but is not, and demands to know how that can be. The Wise One descends tells him everything: Back when the Elemental Stars were first pilfered by Alex and Saturos and they had to leave Sol Sanctum with the Mars Star in Isaac's possession, the Wise One predicted Alex's motive and set in effect a precaution to counter it. By imbuing the Mars Star with a certain magical property, the Mars Beacon generated by the Mars Star at Mars Lighthouse ended up imbuing its essence of power into Isaac's body at the lighthouse rather than Alex's body here at the peak of Mt. Aleph. The Wise One and an unwitting Isaac have thus robbed Alex of his dream for complete mastery of the building blocks of reality. Triumphant over the success of his grand plan, Alex eagerly tests his newfound power by calling out to the sky for a thunderstorm to be summoned and unleash its might upon the now-empty town of Vale at the foot of the mountain. To his puzzlement, however, not even so much as a simple storm appears. He barely has time to ponder the meaning behind this when he is suddenly greeted by  the Wise One, last seen in Sol Sanctum as the guardian of Alchemy's seal. The Wise One announces that Alex has indeed gained a lot of power and life, but they are by no means limitless. Alex, believing the Wise One is trying to anger him, confidently pushes the Wise One away with his bolstered Psynergy, but the Wise One telekinetically drives Alex into the ground and completely immobilizes him.

Then, the entire mountain and its surrounding landscape begin to change and collapse as part of the last phase of the process that signifies Alchemy's release. The Wise One instructs Alex to flee the mountain if he wants to save his own life, lest he be "drawn into the heart of the earth forever." Alex exclaims he is unable to even move right now, to which the Wise One responds that now Alex sees the limits of his power, and that Alex may not survive his imminent fall. The last words Alex hears before he meets his supposed demise is this cryptic final statement by the Wise One: "If you survive, perhaps we shall meet again someday..."

In Dark Dawn

Alex managed to survive the fall into the Earth, and masked himself so nobody recognized him (he was presumed dead). Ten years after the restoration of Alchemy, he stumbled across a city called Ayuthay, and fell in love with King Paithos' sister, Veriti. He turned Ayuthay's Alchemy machine, the Alchemy Well, on halfway (the other half required the Luna Mask, which he did not have in his possession). He also revealed his face to only Veriti, and together conceived a son, Amiti. However, he ran away for reasons unknown, and King Paithos lied to Ayuthay and said that Veriti had powers which allowed her to turn on the Alchemy Well, and to get pregnant without a male partner, in order to keep the Mysterious Adept (aka Alex) a secret. Later, identifying himself as Arcanus (Ace in the Japanese versions), he joined up with the Tuaparang, working with Blados and Chalis. Alex's motives throughout the game are unknown.

Alex, under his guise of Arcanus, teams up with the two Tuaparang agents Blados and Chalis, similarly how he had teamed up with Argaito and Karst and Saturos and Menardi thirty years earlier. The Masked Man and Blados kidnap Rief, a Mecury Adept, and manipulate the descendants of the Heroes of Vale into wandering off-course, blocking their path back home. Alex and the two Tuaparang elites approach the beast king Volecheck, and turn him to their side without him knowing he's being used for the High Empyror's own needs.

Alex, after Blados and Chalis are defeated at the Belinsk Ruins, uses Ryu Kou, an apprentice to Hou Zan and friend of Matthew, to turn on the Alchemy Dynamo under threats of the martial artist's sister, who is due for execution at Volecheck's hand. After the Alchemy Dynamo is activated, Alex takes Blados and Chalis and leaves, while the Eclipse Tower rises from the Belinsk Ruins. The Grave Eclipse, an eclipse that covers most of the continent of Angara of shadow, starts, furthering Alex's goals even more. Alex doesn't appear again until Matthew and his party reach the Apollo Sanctum, where the Apollo Lens, a device that can stop the Grave Eclipse, is ready to be activated. Blados and Chalis confront Alex, intending to use the Apollo Lens for their own purpose, but at this point Kraden reveals Alex's true identity to the Heroes of Vale, and Alex vanishes. Blados and Chalis confront Matthew, as well as the Chaos Hound (later revealed to be a mutated Volecheck) and fuse into the Chaos Chimera. Even after the Chaos Chimera is defeated, Alex is heard telling Matthew to stop, telling him he cannot use the Apollo Lens without dying. Volecheck, still as the Chaos Hound, ends up sacrificing himself to fire the Apollo Lens and stop the Grave Eclipse.

Alex disappears and doesn't reappear in the game after this point, and with the game ending on a cliffhanger, his ultimate fate is unknown until a possible fourth installment of the series.