The first few times that Denji and Power are placed together, they do not get along. Why does Denji not like Power?
Denji does not like Power because she’s narcissistic, self-centered, a pathological liar, and a racist. He sees her as a problem, but the two grow as friends as the story unfolds.
Some of Power’s rougher edges soften up as the show goes on.
Denji decides he does not like Power
Chapter #43 begins with Denji weighing the pros and cons of the different women he’s met. He tells Pochita, in his head, that he likes two different girls and can’t decide who to be with.
Denji says he doesn’t prefer the Angel Devil, as she might not be the girl he’s expecting. Kobeni is short and cute, but she tries to attack Denji, so she’s out.
Power, Denji says, still tries to attack him once and awhile despite their friendship becoming better. Denji says that she is narcissistic, self-centered, a pathological liar, and a racist.
The decision between Makima and Reze is a difficult one for Denji.
The specifics behind why Denji initially dislikes her
But, let’s talk more about Power. Denji says she’s narcissistic, as she speaks very highly of herself and her devil-hunting abilities. She is indeed self-centered, never offering to help clean up Aki’s apartment and often leaving it a mess for others.
Power being a pathological liar is one of the key reasons he does not like her. In chapter #5, Power breaks the rules and attacks a devil without permission. Makima explains that it’s considered an obstruction of justice when a Public Safety Hunter attacks a devil that a Civilian Hunter is already engaged with.
Makima questions Power’s ability to remain a devil hunter. Since she’s the Blood Devil, battling makes her too excitable for the job.
She then lies, accusing Denji of instructing her to interfere with the Civilian Hunter’s job.
Despite Denji not liking her at the time, she actually grows on him as the series goes on. Power proclaims that the two are considered “buddies” and best friends towards the back half of Part 1.
Power even decides to bring Denji a cake to celebrate his birthday, further cementing their friend-status.
So that’s the answer. Denji does not like Power because she’s a pathological liar, amongst other bad things. The two grow as friends over the course of the show, however.