Doom Breaker (Dude get's K'd by demon god but gets a re-do with all his knowledge and couple of skills, 101 chapters webtoon)

 To start off, and while apparently superfluous, very relevant, the artwork is great. I realized how important that is AFTER I finished reading Doom Breaker and end up reading some other webtoon and was deterred by the lifeless eyes and disproportionate limbs.

 Also, the fights are mostly discernable except a flash of lights here and there that's mandatory in a magic fantasy comic, which again may seem "duh" to anyone inexperienced that hasn't suffer from the dragon ballz like shonen "too fast for the eye to see" fights which is basically like looking at the Windows screensaver.

PR: Following the desire of power, presumably maybe they're just idiots, the Demon cult of the God of Destruction (are we the baddies?) summons this world-consuming entity after a few decades or centuries of thorough planification and effectively bring apocalypse onto the world.

 I say "idiots" because same as those super-villains hell-bent on destroying the world, they were left with nowhere to live.

 Anyway, like the saying goes the world is full of idiots and that means is full of Tartarus Worshippers (Tarts), it's like that racist guy in the online chats there's always at least one, but since the protag already knows the identity of these while having limited power (in theory) he manages to thwart a lot of the Tarts plans. As the story left, he had to slay all the dragons in the world to acquire enough raw power to fend off the inevitable demon invasion. 

While far from original the story read easy and it's entertaining, coupled with good art and decent/neutral characters (non-hateable) it's one of the best manhwas I've read 8/10