searching for a korean manhwa, mc was blond/brown hair, ML black hair. It was a post apoca...

searching for a korean manhwa, mc was blond/brown hair, ML black hair. It was a post apocalypse (?) world, and MC was keeping his friends corpses(zombie bodies????) at his house. ML proposes a contract of some sort to help him put them to sleep or something like that in exchange for his power.