Aki Hayakawa is a dedicated and stoic Devil Hunter who works for the Public Safety organization. He's driven by a deep desire for revenge against the Gun Devil, which tragically killed his family. Aki wields the power of the Future Devil, allowing him to see glimpses of the future, and the Curse Devil, which lets him inflict immense pain on his enemies by sacrificing a part of his lifespan. He's often seen as the responsible one in his group, trying to keep the more reckless members, like Denji and Power, in line.

Denji is the main protagonist of Chainsaw Man. He's a young man who starts off living a life of extreme poverty, working as a devil hunter to pay off his deceased father's debt to the yakuza. His life takes a wild turn when he merges with his devil-dog, Pochita, becoming the hybrid known as Chainsaw Man. Denji is characterized by his simple desires – good food, a comfortable life, and a girlfriend – and his often naive yet surprisingly resilient nature. Despite his rough upbringing and the extreme violence he faces, he retains a certain innocence and a strong, if sometimes misguided, sense of loyalty.

Power is a Blood Fiend and a member of the Public Safety Devil Hunters. She's incredibly selfish, chaotic, and absolutely loves causing mischief. Her primary motivation is often self-preservation and her own amusement, though she does develop a strange sort of bond with Denji. Power's abilities revolve around manipulating her own blood to create weapons and attack. She's also incredibly arrogant and believes herself to be the superior being, often looking down on others, especially Denji. Despite her often abrasive personality, she can show moments of surprising courage and loyalty when it truly matters.