Manga by author Kim Yong-hwan

From: Easy Going ScansA Demon Lord spirited the Princess away, and cursed her with eternal sleep. Countless knights sought to save her, only to die in vain by the Demon Lord's hands. But then, a Nameless Knight arrived to vanquish him and save the Princess, ignorant of what fate had in store for him...

After saving the girl he loves, Sahu incidentally turns to a zombie. And now he's trying to survive in a stone jungle, believing that one day he will sing for the world.Webtoon from Daum