Undead King ~A Low-Ranking Adventurer, With the Power of Monsters, Becomes Unbeatable~ is a Manga/Manhwa/Manhua in (English/Raw) language, Action series, english chapters have been translated and you can read them here. You are reading chapters on ManhwaZ fastest updating comic site. The Summary is

(skills). A power humans can only receive once from god, which is used to fight against monsters. Chrome, who aspired to be an adventurer while owning a skill that is useless in combat, is unable to throw away his ambition, and is despised for his inability, so he is left in charge of menial tasks and chores for his career. But, when he is running away from a monster as a decoy, he loses his life. But at that time, his skill activates. The skill (Revival). For one time only, he can come back from the dead, and Chrome miraculously revives as a Skeleton monster, a “Wight”. Chrome, who despairs at his new body, finds out that as monsters evolve, their appearance changes in accordance, so he decides to evolve as fast as possible. Believing he can regain his human appearance, Chrome spends his days hunting monsters. As a by-product, Chrome gains a multitude of skills, whereas a human can only ever hold one––! Powerful monster abilities and the intelligence of a human. Overcoming adversity with chance, Chrome once again aims to be the strongest adventurer!