The King of the Battlefield by Onhu

Translated from Korean Action Adventure Demons Fantasy Game Elements Mature Supernatural Time Travel Transported to Another World Undeads
Recommended for those who like fast paced, reincarnation stories. Muyoung is a badass and the world is cruel. Although Muyoung doesn’t think like a normal person, everyone who has lived long enough in the Underworld is NOT normal. He also was the ultimate assassin for forty years before he died trying to kill people who manipulated him against his will.

Author’s Synopsis:
Amidst the war between 72 Demon Gods, humanity was defeated.
Muyoung steps into the past to fix their mistakes.

Myoniyoni’s Synopsis:
Humanity was on the brink of destruction. Muyoung, an assassin from the Forest of Death, fell to his knees. There were corpses all around him. For years, he had worked for the Forest of Death and had finally been able to eradicate them. Now, he, himself, was about to die. He closed his eyes as he felt his heart stop beating.

Suddenly, Muyoung opened his eyes. By some miracle, he was still alive. He then realized that he had actually gone back 40 years in time. Join him as he decides to fix humanity’s past mistakes and fight against the 72 demons of the Underworld.

Alternative names : KotB

Chapters 0-51