Ritsu Shikishima is the main character of the Caligula anime. Like his game counterpart, he is a second-year student at Kishimai High School. It was during the end of his first year when he starts to notice incongruities within his world, eventually learning that Mobius is not the real world. Ritsu is shown to be highly intelligent and knowledgeable, evident by his readings of psychology and, more recently, philosophy. He is notably close to Marie rather than Naruko was in the game. Ritsu also likes to question the mind's way of thinking, hence his interest in psychology. Ironically, this is what allows him to realize that the world he is in is not the real world. He pretended that this realization didn't exist, but he slowly understands that everything is not how it should be.