Haku is an exceptionally powerful demon, defeated countless Demon Slayers in the past. He is often irritated, silent, and aloof, maintaining an aura of unnerving tranquility and mystery. He rarely speaks, he talks in a slow and emphatic manner that gives more gravitas and authority to his words. Despite his stoic nature, he is shown to be secretly protective and caring towards his human-side’s loved ones. He once placed his life on the line for his childhood friend, Mitsuko the now Star Hashira.