Kato is a formal and upfront man who has a dream of becoming a successful and famous pianist in the future, and had been playing piano since he was merely six. After having joined the conservatory, the desire to be successful had been getting the best of him, resulting in him murdering those who he saw as better, or would belittle his skills. But Kato always covered it up amazingly, and doesn't ever let his more sadistic side show.