I don't know how to feel about the MC. So far he seems like a huge jerk, to say the least. Feels kind of annoying that someone as horrible as him gets to have a second chance.
My guess is that's it's the whole "warrior in time of war = hero, warrior in time of peace = mass murderer/villain". Not sure good/bad he is on this chapter alone, but he seems like he have a short fuse. Which work fine when he's in a sea of monsters, but not so much when the world start figuring out how to fight back & able to catch their breath long enough to start pointing finger.
The karma/revive thing probably because the dungeon he clear would have killed many more if he didn't clear it, so by clearing it, despite being an asshole, he net positive.