Aki Hayakawa/History

Intro arc
When Hayakawa is first introduced, Makima orders Denji to work with him. While they are patrolling the city, Hayakawa becomes annoyed with Denji asking whether Makima has a boyfriend and pulls him into an alley to beat him up, as a warning that if he doesn't take Devil Hunting seriously he could end up dead. Denji then fights back, kicking him in the groin multiple times and stating that he would risk his life to continue living the way Makima has shown him. Once they get back to the Devil Hunters Headquarters, Makima assigns Denji to Hayakawa's squad.

Bat Devil arc
Aki drives Makima from her meeting with her superiors. In the car, Makima explains to Aki that she is interested in Denji because of his ability to transform into the Chainsaw Devi. As Denji is impaled by the Leech Devil's tongue, Aki arrives at the battle. He summons the Fox Devil to devour the Leech Devil and save Denji. After taking Denji to the hospital, Aki explains that he was able to summon the Fox Devil as he made a contract with it, and that he allowed the Fox Devil to consume a part of his skin in exchange. Aki expresses his disdain for devils to Denji, claiming that they cannot be trusted. Aki informs Denji that he knows that Power tried to kill him, which Denji denies. Aki then threatens to report Power, along with Denji for covering for her, and have them executed if they do not obey his orders as their superior.

Makima informs Aki that Power is going to be moving into Aki's apartment, to his dismay. Both Aki and Denji yell at Power for never bathing or flushing the toilet.