I'm looking for novels where mc has a terrible toxic personality but it's done so intentionally by the author. Preferably good writing, whatever it may mean
https://www.novelupdates.com/series...somehow-recovering-in-a-world-full-of-miasma/ Well, at least if you hadn't written down that "personality" there... :/ Ah, other than that not much idea here... most of the JP MCs are toxic people, but they're probably not "intentional" as you desire. F.ex. https://www.novelupdates.com/series/hachinan-tte-sore-wa-nai-deshou/ by ch 69 https://www.novelupdates.com/series/tsuki-ga-michibiku-isekai-douchuu/
Spare Me, Great Lord! maybe, but only to the level of words and maybe harmless actions. Still hilarious though.