Just some musing here. I don't like grimdark, especially not in superhero comics, and not much generally. But like any taste, it has fuzzy edges, and there is some such material I am actually able to appreciate. I thought I'd begin with what I think is the most evil number one single ever recorded.
Ruby, Don't Take Your Love to Town is a mini-masterpiece of sick-mindedness, with its tale of a crippled war veteran fantasizing about his wife's affairs, and wishing he could move so he could murder her. It's evil. I wish I had thought of it.
What makes this so deliciously evil is that from the listener's viewpoint, the narrator is in no position to know whether or not the adulteries he sings of are real or not. We can't be certain whether the woman is actually having these affairs, or whether they are entirely the fancies of a man who's in no condition to investigate them; all that he knows is that she is out of sight in places he cannot follow.
What we do know is that he wants to murder her, and wishes that we were able to move so he could do the deed. That is pretty nasty in itself. Yes, of course, it's sexist, and treats women as property. The audience for which Mel Tillis originally wrote it apparently found nothing unusual about it. Violent sexual jealousy was a fact of life they accepted. (And they may as well; it isn't like there's anything that can be done about it.)
What amuses me is that Kenny Rogers, Mr. Whitebread MOR Pop-Country Christmas Special himself, rose to fame with material like this. Later in his career, Rogers recorded Roger Bowling and Billy Ed Wheeler's Coward of the County, a song that's perhaps even more sick-minded than this one, but with a much more straightforward narrative that lacks Ruby's subtlety. But both pieces are a portrait of a nation whose mainstream tastes are sick in mind and soul, which is why I love them despite myself.