Roy is a common student (and kind of bully) at day and an assassin at night, specially on Halloween. He's quite grumpy and low-tempered, being mocking-toned even, and surprisingly isn't any sort of "psychopath". He kills either out of boredom, to relieve stress or for justice, and NEVER takes an innocent person's life, always must have a reason to do so. Hides his identity as much as possible, calling himself "Slaughter"; but secretly he also nicknamed himself because it's cool.