As for the outline, it's all very generic. Everything takes place in some fantasy world into which our MC possibly reincarnated (can't remember). There's an academy arc during which he's honing his magic, later on he goes on to fight some demons, etc. The only concrete thing I remember about the story is this: for around half of the novel's length we hear tales of a famous human wizard of the previous era who helped defeat some great evil only to mysteriously disappear soon after. Later on our MC crosses paths with him, only to discover that supposedly incredible hero is living with the elves, but due to the anti-human bias he's treated like a second class citizen. If I'm remembering correctly, he also has a half-elf daughter that our MC kills or hurts at some point in the story. SOLVED: Advent of the Archmage
I skimmed through "Law of the Devil". but I don't think that's it. My memory is extremely fuzzy, but I think the setting was closer to "reincarnated in a game world" rather than the usual xianxia reincarnation. Much of the school arc was spent in preparation for some demon awakening that MC was aware of... probably. It's been years and dozens of samey novels since I read it. Honestly, the only thing I'm sure of is the whole deal with that great mage or wizard who turned out to be living with elves. The whole story was spent hammering in how the human magic was underdeveloped and inherently weaker than that of the elves -- except! -- for that one mysterious hero. And then we learn he resigned himself to living with the elves, trying as hard as he could to integrate himself, but clearly being scorned and despised. A brilliant monkey, but a monkey nonetheless sort of deal.
Yeah good luck with finding that... Its seems that the novel you're looking for is not popular bcoz i'm the only one who bothered answering your post (even though its wrong)