With no memories, family, or any past at all, Sigma has been described as a desperate boy. Someone who would latch onto anything that gives him a reason for his existence, that at the moment being his classes. He puts up the perfect act of the perfect student, always putting up a front of being calm and composed, going out of his way to help his classmates. Though, Sigma is a deeply insecure individual, panicking at any small inconvenience. He's deeply anxious and insecure.