Gwiwangchulsa

As the son of an undertaker and a coffin seller, Gunak is pursued by the Geumgeomseong while searching for the secret story of the mysterious sect, the Galaxy Heavenly Palace. Gunak, who fell into the evil group Jijungcheon, meets the legendary Fantasy Martial Arts Immortal and is resurrected as the Ghost King to avenge his father and the four great sects. In the midst of a flurry of schemes and conspiracies, the Four Hegemons clash, and the righteous Ghost King who punishes evil is the afterlife!!

(Source: Mr.Blue, translated)