Clan Rise: Starting as a Grandfather - Chapter 3 - 2 Becoming a Widower, I Can Also Remarry

The Great Norther Wall. The Dragon Knights. The Lords of the Winter Mountains. The Descendants of the Primordial Dragon. These are the various titles of the Grand Ducal Clan Ragnar, which boasted a rich, thousand year history. Theo Ragnar resolved himself to aiming for the throne of that very same clan. ‘These cursed chains weren’t something I could slip out of. They were meant to be broken with strength.’

In a world shadowed by death, the silent realms await, home to the undead and the Grim Reaper's sanctuary. As long as death's presence endures, the great Undead Queen will return.

Have you ever thought that the state of the world as it presently is, could revert to the laws of the ancients? When a series of strange incidents beginning with the disappearance of his friend led Luo Yuan to question the possibility of an apocalypse, he becomes embroiled in the midst of a global-scale chaos.

Evolution has turned the flora and fauna of the vast and bountiful Earth into something that had never been seen before. Coincidentally, the all-dominating Homo sapiens have ended up at the bottom of the food chain. From mystery to crisis, will Luo Yuan discover a means of saving humanity by racing to the top of the food chain? Or will he strive in accordance with the law of the jungle? It is the dawn of an age of the survival of the fittest.

- Description from Novelupdates

This is a story of a man named Kim Sae-Jin, who one day, inexplicably wakes up as a Monster. Follow him and his perilous journey to get his life back as a Human, all the while growing even more versatile as a Monster in the process. This should be… complicated, somewhat.