Aki Hayakawa has a stoic, mature, and responsible personality, but underneath this exterior is a compassionate and softhearted individual who cares deeply for his friends. His serious demeanor is a defense mechanism driven by his past trauma from the Gun Devil, which fuels a relentless desire for vengeance. He values principles, gets attached to people easily, and is extremely protective, though he often expresses his frustration with the immaturity of others, particularly Denji and Power. 