It was an on-going translation ( 100%) when I read it for the first time and I lost its trek in my reading list long ago, so now I have only some vague flashbacks and they do not help much. MC is a clever guy, that's for sure, because in the story he kinda chases the bad guy and one day he appeared near the sect school where there were many girls of different origin. The bad guy wanted to kill ( or to kidnap or to marry one of the disciples to steal her powers, idk) and for saving the victim, MC (maybe disquised, I think) made a plan. He began selling jewels in front of the school to the girls and telling them different stories to warn them up against the bad dude They saved the girl at the end but it was maybe from another story (?) where there was a black smog/magic and the guy ran away. Sorry that's all I remeber, any thoughts?
@xiaoyigege is right regarding your last sentence... that black "smog" and the guy who ran away is indeed from Heroic Death System, Arc 3 - You are my faith (Ch. 20-32) and Arc 3 RE - You are my faith (Ch. 119-123) Regarding the first one, let me think... If I'm not wrong, isn't it from "There Will Always Be Protagonists With Delusions of Starting a Harem" ? Namely... Arc 6 - The dormant Demon King (Ch. 62-70.2)
Hmm... The only xianxia BL story that I know of that has the slightest resemblance to what you are describing is "The Demon Venerable’s Wistful Desire". The MC is pretty clever in my opinion and he does go around saving girls if I remember correctly. He does a lot of dressing up/disguising while he is escaping/hiding from the story's ML