Isekai Saikyou No Daimaou, Tensei Shi Boukensha Ni Naru (Associated Names)

Lucifer, who is said to be the strongest and most evil demon king… However, he was the hero who tried to protect the people who were abandoned by God. He went to sleep to heal the wounds he had sustained in his battle with God and awoke a thousand years later. What he saw was…