Even

Even was one of the six apprentices to Ansem the Wise, and the complete being of Vexen. He appears in Kingdom Hearts Birth by Sleep through the Tokyo Game Show 2009 Kingdom Hearts Birth by Sleep video, in which he is seen talking to Ventus, wondering aloud if the two will have a connection in the future. In a similar scan, Ienzo has been seen standing next to him during this conversation.

Dabbling In Darkness
About a decade prior to Kingdom Hearts, Even was one of six apprentices to the ruler and scientist of Radiant Garden, Ansem the Wise, alongside Xehanort, Braig, Dilan, Aeleus, and Ienzo. Worried the Darkness in people's hearts would eventually consume his world, Ansem began performing tests on Xehanort's heart, which Even showed particular interest in. Eventually, he created a laboratory in his castle's basement for such experimentation. However, Even 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, Even and the other five apprentices dabbled too deep into darkness through their continued experiments. Even, along with the others, was consumed by the darkness, producing a Heartless. However, the apprentices all had strong wills, and so Even also became his Nobody, Vexen. The six Nobodies formed Organization XIII, and banished Ansem the Wise to the Realm of Nothingness.

Appearance
His appearance matches his Nobody, Vexen's, exactly, except for the differing outfits. Even wears a long white lab coat, grey vest, white collared shirt, and a purple ascot. He also seems to wear black pants and silver lined boots identical to those worn by Organization XIII members.