Technically 20 years old, his insanity makes him appear as though he is in his teens. He loves pretending he is a mad scientist, and whenever a torture session is needed, it is usually headed by Roy. He has an unusual air about him and a very prominent child complex. He loves acting like a little kid.
He has no favorite weapon, as he likes playing with his 'food'. But for practical purposes, if he's sent on a mission he will usually take a katana with him. With long red hair and a longer white doctor's coat stained with blood, this man is particularly androgynous.
With help from Mercain and Amigo, Roy is able to invent things. One of his prized inventions is the RezSuspend, a machine able to cancel out anyone's resonance soul, rendering them unable to defend themselves by supernatural means. Eventually they plan to perfect the machine so it will take the form of something smaller that be placed on the body. Of course, Roy, being one of the big brains behind the project, seems to get sidetracked too easily. The project hasn't gotten very far. Although, it didn't have to, as the men all learned later that something similar to their invention already existed, called Limiters.
Roy's Rez is the ability to regenerate limbs and body parts, as shown in Chapter 11. Later he works in an underground facility to create an androgynous “perfect lifeform” named Sin. This vessel has no soul and was created in the image of Roy as a host for the combined Pheonix Soul and Soul Stealer. In following chapters, it is shown that Roy can be quite sane when he needs to be, although he constantly has to be reaffirmed by Amigo, whom he calls his father, that he is doing a good job.