Being over three hundred years old, rei has experienced many different things in life and yet he still possesses the reckless spirit of which he had attained from his younger years. His flirtatious attitude was also something he was never able to rid himself of.

Rei Katoka was born into the Himura clan, his father, one of many drug dealers, and his mother, a e; which is kind of a funny story of how they met. His conceivement was what one would call "accidental," though his parents gave him as much attention as they were capable of giving. As a child, he would constantly be causing them much of a headache for the trouble he would get himself into. Just something about being mischievous felt right to him, hiding his true self behind a wall of destructive behavior.

When the vampire was around two hundred years of age, both of his parents mysteriously disappeared; it started with his father going missing and then he lost his poor mother late one night. It was unknown as to what had happened to them, if they were kidnapped or murdered, the only thing he wished for was that he could have at least gotten a chance to say goodbye. With both of his parents gone, he was left broken, feeling as if a piece of him had been torn away. Most of the time he masks his pain with a smile and his playful attitude, laughing off sensitive situations in an attempt to protect himself from getting hurt. Although rei tries to cover up and avoid any circumstance that could possibly cause him pain, the hurt of his past is still clearly prominent in his eyes.

The assassin takes his job very seriously, probably being the only thing that he takes seriously. But that is strictly only when he is seeking out to kill. With his teachers, the elders and basically anybody who has authority over him, he enjoys testing his limits with them. Seeing how far they will allow him to go, simply just trying to annoy the hell out of them with a little flirting added into the mix. Being better at gravity manipulation, he chooses to use that power a little bit more than the others. He finds telekinesis to be more of a struggle and his precognitions come in bits and pieces rather than in full. He practices them every now and again, though, mainly when he is alone to save him the embarrassment.