Gaku is a tall young man in his early twenties. He has bluish grey hair styled in a slick back manner and red eyes. He is an extremely calm, nonchalant and laidback individual who always talks calmly and rarely gets agitated or angry, even during fights or life-and-death situations. Gaku often compares real life to a video game, describing a deadly injury as a "speedrun to death". He is very uncaring about the lives of others and can kill without hesitation. He was an orphan at the Al-Kamar.