Calcifer

When he says hyeong he's just saying 'hyung'

Oh so that's how it is? I would never have guessed that! But thank you so much for your reply ♡

chapter 59 gives me more of Sangwoo from Killing Stalking vibes ヾ(☆▽☆)

Bloody Nora! Didn't think it was possible for this psycho to get any worse (⊙…⊙ )

I mean, he is definitely up there among the more toxic and self-absorbed black flag tops around that don't even try to change for the better because lOvE, although Garon (Toxin), Zigryl (The Flower of Alosha) and Seo Haeyoung (Non Zero Sum) are still worse. I am sure, there's more of them around, if I think hard enough about it...
Not even Kang Moo (The Beast must die), who is a (in universe) diagnosed psychopath or Zhenya (Codename Anastasia), who, I am pretty sure is heavily implied to have ASPD as well (and who both kill people fur funsies) are quite as bad as those three. Or Lee Wooyeon (Love History Caused by Willful Negligence), who is also diagnosed with ASPD (and acts the part).
But at least those three kinda grow (I know, the bar is in hell) as much as they can, given the circumstances, and TRY to treat their S.O.s better at the end of the story. Kangwoo falls more in this category than the former (completely nonredeemable tops).
Still not a good partner to be in a relationship with, but hey, again, the bar is in hell...and it's just fiction, thankfully.

Oh I don't think I've read anyone of the ones you mentioned ⁄(⁄ ⁄·⁄ω⁄·⁄ ⁄)⁄ guess black flags are in fashion (￣∇￣")