Houjuuibo

One rainy day, Ji-Oh's childhood friend and crush, Woo-Jin, becomes possessed by a ghost in an accident. Ji-Oh couldn't just sit by and watch, for Woo-Jin had been his savior, holding him back from his straying ways. So, Ji-Oh teams up with the psychic Gyeon-Woo to restore Woo-Jin's body. After a series of twists and turns, they temporarily succeed in exorcising the ghost, but the ghost and Woo-Jin's soul begin to interact...

(Source: Ridibooks, translated)