Nayuta/History

Control Devil arc
After the defeat of the previous incarnation of the Control Devil, Nayuta incarnated in China as the new Control Devil. Kishibe found her in China and brought her to Japan.

During the meeting between Kishibe and Denji, Nayuta approached them by hugging one of Makima's dogs. Kishibe introduced her to Denji while she was biting one of Denji's fingers. Denji remembers this bite from the time Makima bit his finger, immediately making the connection between the two. Kishibe goes on to say that Makima is effectively gone, and this new Control Devil must not be allowed to go down a similar path, thus leaving Nayuta in Denji's care rather than the Public Safety's.

Justice Devil arc
Nayuta was sleeping with Denji and their dogs while Yuko was beheaded by a figure resembling Chainsaw Man. Later, when Denji and Asa Mitaka are trapped in the Tanashi Aquarium by Fami, Denji reveals that, despite her young age, Nayuta is smart enough to go to college, and he is paying her tuition.