Just came across this question and had to chime in because I spent way too much time digging through archives for this exact thing last year. The dynamic is so messed up but that’s what makes it compelling, right? A lot of fics either make Eto too soft or turn Kaneki into a pure victim, which misses the point. Their bond is built on mutual manipulation and a shared hunger for understanding, not just romance.
I found one on AO3 called 'The Owl's Nest' that really gets into the psychological games. It’s a slow burn where Kaneki, post-dragon, is trying to piece himself together and Eto uses that vulnerability to pull him back into her world of stories. The prose is intentionally disjointed, mirroring Kaneki’s fractured mind, and the dialogue between them is less about declarations and more about layered taunts and revelations. It’s dark, not very romantic in a traditional sense, but it nails that eerie codependency.
Another darker, more niche one is a crossover-ish fic on FFN that blends elements from 'Tokyo Ghoul' with a sort of gothic horror vibe, where they’re both immortal beings haunting the same spaces over centuries. It’s less popular but captures the timeless, predatory aspect of their connection. The ending is deliberately ambiguous, which fits them perfectly.