Sasinsonyeon

Lee Kyung-Ho’s mind was engulfed with ending his life due to bullying and the loss of his mother. His determination to commit suicide entices Sierra, a grim reaper who later offers him a contract. This contract blesses him with the ability to borrow the powers of the dead in exchange for sacrificing years from his lifespan. In order to get what he wants, he ends up accepting it...

(Source: Webtoons, translates and edited)