Absolute Necromancer Manga

A brief description of the manhwa Absolute Necromancer:

Tower. Mysterious location with plenty of quick shifts. I reincarnated as a boy who lives on Earth in South Korea ten years later. “I’m going to rip into the guy who backstabbed me and the one above him.” Spirit Master Cha Jinhyuk was the necromancer who rose to the top and attained the next class. He will exact retribution as the “All-Master” by scaling the tower in the form of a necromancer (spirit master).

[By the studio that brought you Standard of Reincarnation!]