Title should be "Simping so hard for a girl that never said "I love you" or vice versa -even right before we were executed- that I stayed undead and am trying to destroy the world in her memory while carrying her bones" the manga.
To be honest, I would have preferred if he killed the king later. This would have made the author add some more nuances to the whole story while possibly adding another whole arc. Also, as far as the whole narrrative goes, he is by all means a simp for still thinking about the girl that is now just a pile of bones, which rises quite a bit of mixed feelings.
Meh at best. Leaning towards garbage. The characters are annoying and the author doesn't understand anything about social interaction or how people work.
This is actually pretty decent. I don't know why people are calling the MC a simp considering his entire existence is built off of a grudge, nor was it ever explicitly stated he was romantically interested in the hero. Whether he was or not is irrelevant anyway, we're just here for a (so far) great Villian story.