Koi wa Hito no Hoka is about a girl named Sayo who doesn't remember that as a young child she'd made a contract with a demon.

Honestly, I'm surprised this one isn't rated more highly. There's a ton of shoujo manga with the exact same beginning premise, and the vast majority of them are very shallow wish fulfillment. This one, however, stood out to me for several reasons 1. Despite the premise, this one was clearly not about setting up wish fulfilling titillating scenes of the demon seducing the girl by dominating her, which is the norm. 2. The focus was instead on the plot, which is pretty straight forward, but serviceable. 3. Sayo is an actual badass protagonist. Though because it's shoujo, of course she's inevitably the one being saved some of the time, she's also doing quite a bit of the fighting herself rather standing on the sidelines as one woman cheering section, which is also the norm. The author did a good job of never making her depend on Yoh so much that she becomes powerless, which is also common.

I suppose if you came looking for another one of those girl makes a contract with a demon wish fulfillment manga you may be disappointed though. And of course don't read it you're rather bothered by the idea of a girl being forced into a relationship, because that kind of thing is unavoidable with this trope. I think maybe it also could have benefitted from being longer, with more details, and more fun character interactions, but in summary, I'd call this one unexpectedly solid.

Oh, I suppose one other thing I should note is that this manga is quite fixated on the idea of demons eating humans, humans eating demons, and so forth. This will make more sense if you know that in Japanese one way to talk about sleeping with someone is to literally say you eat them. Although the demons literally mean eating, the reader is also probably supposed to have the more sensual interpretation in mind, especially when applied to Sayo and Yoh.