I'm looking for a story I forgot the title of. I don't remember all that much, but the protagonist was a powerful cultivator, who reincarnated in a "young lord's" body. I think that the young lord was either handicapped or just an asshole, but I might be mixing it up. I do remember that the young lord had a fiancée that didn't care much for the young lord, but the protagonist wins her over after reincarnating. There was an early auction house plot because the young lord had some debts to pay I think. I think that the young lord, and after reincarnating, the protagonist, had a fat friend aswell.. The one thing that stood out, that might help you narrow it down a bit, is that the protagonist before reincarnating had a wife or dao companion or some such, who's still alive and will play a part in the story (never got so far that they met up again). I'm thankful if anyone's got some ideas from my admittedly vague memories!
Rebirth of The Heavenly Demon i think. Not sure . EDIT : there are two of them its this one i believe (link)
That's the one, thanks! E: Or rather, Realms In The Firmament was the one, but it's a shared universe so you helped me find it!