@BananowyJE: I’m not so sure that they’re antithetical to Nomen, since it seems like their personal obsessions are synchronizing. Both of them wanted to leave their former selves behind. The difference between them is that Yadori wanted to live the life of someone else happier than him while Nomen wanted to escape the concept of the self entirely.
And then Nomen went off-track from his obsession and has settled into his identity of Nomen, according to Chiharu. On the other hand, we have Yadori here feeling like the happiness he feels from becoming someone else is hollow when he can’t even care for himself. There’s kinda a cyclical relationship here with them not being happy with who they were and finding happiness in their new “identities”, except Yadori is kinda cycling back into Nomen’s original disposition, at least from what I can read into this chapter.
Also, I don’t think he can mimic powers. There was a frog left out at the end of the last chapter, which I assume was what transformed that guy he just ate. It seems like Yadori are everything about them except for the frog, meaning no powers.