Majority of information taken from The Keyhole-Lexaeus.
Lexaeus, the Silent Hero (静かなる豪傑, Shizuka-naru Gōketsu?), is the Nobody of Aeleus and is Rank V within Organization XIII. He wields control over earth and uses his massive Skysplitter Axe Sword to create earthquakes and brutally slam opponents.
Lexaeus appears in Kingdom Hearts: Chain of Memories during Riku's storyline, working with Zexion and Vexen to try and manipulate Riku into serving them. In contrast to his fighting style and physique, he is a disciplined schemer who often tries to keep people such as Vexen in line. Lexaeus appears in Kingdom Hearts 358/2 Days as a playable character in Mission Mode. Tetsuya Nomura said that Lexaeus "has slow movement, but has very high attack power."
Kingdom Hearts Birth by Sleep
Aeleus is shown guarding the palace of Ansem the Wise. He and Dilan meet Ventus, but keep him from getting inside the castle, telling him to leave before the monsters come out. Aeleus then spots an Unversed, and both guards begin to head after it as Ventus runs ahead of them. As the two move to follow him, Even approaches and openly wonders what will become of the castle if they left their posts. Aeleus begins to argue, but Even assures Ventus could handle it because he is "special". As Aeleus questions this, Dilan recalls their job to guard the castle, and the two return to their positions at the door.
Between Kingdom Hearts Birth by Sleep and Kingdom Hearts 358/2 Days
About a decade prior to Kingdom Hearts, Aeleus was still one of six apprentices to the ruler and scientist of Radiant Garden, Ansem the Wise, alongside Braig, Dilan, Even, Ienzo, and Xehanort. Worried the Darkness in people's hearts would eventually consume his world, Ansem began performing tests on Xehanort's heart. Eventually, he created a laboratory in his castle's basement for such experimentation. However, Aeleus and the other apprentices had their own intentions for the laboratory, and began conducting inhumane experiments on the human heart and the darkness within it. Such experimentation led to the creation of Heartless. Ansem quickly discovered their secret experiments, and immediately ordered them to stop. One day, after being advised to review their research data by King Mickey, Ansem found that the effects of their experiments had become irreversible.
Eventually, Aeleus and the other five apprentices dabbled too deep into darkness through their continued experiments. Aeleus, along with the others, was consumed by the darkness, producing a Heartless. However, the apprentices all had strong wills, and so Aeleus also became the Nobody Lexaeus. The six Nobodies formed Organization XIII, and banished Ansem the Wise to the Realm of Nothingness.
Kingdom Hearts 358/2 Days
Lexaeus appears once again in the Kingdom Hearts 358/2 Days, this time with a much smaller role, appearing only in the beginning tutorials. Present when Xion joined the Organization, the Silent Hero trained Roxas in Twilight Town before being sent away to Castle Oblivion. While tutoring the Keyblade wielder, it was this Nobody's responsibility to teach Roxas how to utilize the Limit Break and survive battle with low HP. He strikes Roxas harshly in the face before the training session to put him on his "last legs". Roxas then had to battle a Mega-Shadow and correctly execute Event Horizon, his Limit, all the while at low HP.
Kingdom Hearts: Chain of Memories
Organization XIII first appears in the series during the events of Kingdom Hearts: Chain of Memories in Riku's storyline. Much of the Organization members' activities centers around the rivalry and strife within the Organization itself. Lexaeus is heavily involved in this feud, which originates from spite between senior members of the Organization and younger members like Marluxia and Larxene.
When Larxene and Marluxia begin to show signs of dissent, Zexion and Lexaeus begin monitoring the castle and their activities. Also active in the castle are Axel and Vexen, two other members of the Organization. Axel is too unpredictable to trust, but Lexaeus and Zexion enlist Vexen's help in spying on Marluxia. After learning that Marluxia plans to make use of Sora's power by deceiving him into feeling loyalty to Naminé, they decide to make similar use of Riku.
Vexen tries to make use of Riku's power by gathering data on him and creating a replica, but his experiments are interrupted. Though he succeeds in creating the replica, he is killed by Axel on Marluxia's orders before he can achieve total control over it, and the replica becomes independent, searching for a heart.
With Vexen gone and the replica useless, Lexaeus takes matters into his own hands, and the Nobody appears to Riku shortly before Sora confronts Axel and Marluxia at the top floor of Castle Oblivion. He tries to sway the former puppet of "Ansem" to give in to the darkness inside him and use his full dark powers. Riku refuses to cooperate, and Lexaeus attacks him, hoping to destroy him if he can not be manipulated. What happens next changes between versions. In the original he uses the last of his strength to attempt to swallow Riku in darkness, resulting in his own death. In the updated version, though the battle is close, Lexaeus manages to knock Riku unconscious. However, Riku's defeat allows Ansem, Seeker of Darkness to take control and he vanquishes an unsuspecting Lexaeus. It is in this moment that Lexaeus realizes whom he was fighting and apologizes to Zexion, stating this was a fight he shouldn't have started.
Day 25: Hollow Ties Author: Lexaeus
Pressing Zexion for answers would be a waste of time. I know that, but this dearth of information is hard to accept. What's happening on the upper levels? What ought we be doing down here? They hug their truths close and leave the rest of us to speculate. Zexion talks of the bond we share as an Organization, but how could such a thing exist? Still, he remains the only one I can trust.
- For more pictures and screenshots of Lexaeus, click here.