It just started getting adaptation but ML from Booty Wurk is a straight up psychopathic black flag. Really black. The type of shit he puts MC through is tough to handle even reading about. He gets even worse in the sequel novel Full Bloom from what I’ve heard.
ML from NZS is a black flag. Can’t really avoid mentioning him.
And less toxic and more like red flags are ML from Monday’s Savior and ML from the Edge of Ambiguity. First one is just dumb and you’ll question your brain cells at how stupid he and MC are. Second one is another psycho that just won’t leave MC alone.
Check out the novel. It’s not all smut smut smut. The author actually did put in effort into building up the world and the atmosphere. It gets kinda interesting to see how events that appeared insignificant at first affected the outcome of the story.
Can’t say anything about Full Bloom though as it hasn’t been reuploaded by the translator yet (the site it was on crashed). But even just the first novel by itself was pretty good imo.

Gimme ur worst. I want a plot where I have to question my sanity and braincells. The darker the better. I prob already read the top dark psychological bl out there. But it's ok just tel me ur favs atleast!