Mawangeul Geumandun Iyu

An era of chaos. The Demon King invaded the human world for generations for 665 centuries. It was the brave men who stopped that terrible war. Through their holy sacrifice, humanity barely survived. But this is the story of a new demon lord. Demon King Demiurge 666 years old. He uttered one word and suddenly left the demon world. “I will stop being a demon lord.” A runaway demon lord and a hero who became his subordinate. What is the real reason he quit being the Demon King?

(Source: Naver, translated)