Aeleus

Aeleus was one of the six apprentices to Ansem the Wise, and the complete being of Lexaeus. He appears in Kingdom Hearts Birth by Sleep.

Kingdom Hearts Birth by Sleep
Aeleus is seen in the Tokyo Game Show 2009's video for Kingdom Hearts Birth by Sleep, in which he is seen serving as a guard and wielding an axe sword alongside Dilan.

Dabbling In Darkness
About a decade prior to Kingdom Hearts, Aeleus was one of six apprentices to the ruler and scientist of Radiant Garden, Ansem the Wise, alongside Xehanort, Braig, Dilan, Even, and Ienzo. 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.

Eventaully, 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 his Nobody, Lexaeus. The six Nobodies formed Organization XIII, and banished Ansem the Wise to the Realm of Nothingness.

Appearance
Aeleus is seen wearing the same guard outfit as Dilan in the Jump Festa 2010 trailer: a grey guard outfit with white cuffs and a red heart on the chest. Aeleus's axe sword is also appears much smaller than his Nobody's weapon.