Gundham has an eccentric and somewhat dark personality, his delusions of self-grandeur likely stemming from an inferiority complex and pseudo syndrome known as chuunibyou. He often claims that he has been blessed with the evil powers of the underworld, refers to everyone else as "pathetic human beings" and claims that even the gods themselves fear his power. He frequently rambles on about being the "Supreme Overlord of Ice" and an offspring of an angel and a demon with an interest in things like the dark arts, alchemy and astral levels. He is often lost in his own little world, preferring to be alone and usually paying more attention to himself or his hamsters than the things that are going on around him, such as in Chapter 1 when he failed to investigate after the murder and putting his lost Hell Hound Earring at a higher priority. As a result, he can come across as rather uncaring and self-centered.

Voice reference: https://www.youtube.com/watch?v=JpjbH-wEodY&t=610s