The story centers on Akira Ono, a regular guy who works at a company that manages an online game. He often plays the game as his character "Maou" Dark Lord. But one day, when he logs on, he is whisked into the game's fantasy world as his character. There, he meets a one-legged girl, and begins his adventures alongside her.
Maou-sama, Retry! (TV Series – ) - IMDb
Fifteen years after creating the game, Oono decides to shut the servers down once and for all. However, as the clock strikes midnight, he somehow finds himself in the body of middle-aged Hakuto Kunai, Infinity Game's Demon Lord! Soon after his mysterious transportation, he witnesses the demon Greole chasing after a little girl named Aku. Although he effortlessly dispatches the creature, Hakuto is still concerned; after all, he does not remember creating the girl or the demon! Doubting whether he truly is in the world of his creation, Hakuto decides to investigate. Bringing Aku along as his guide and companion, Hakuto sets out on a journey to find out exactly who or what summoned him to this fantasy world—all while leaving chaos and destruction in his wake.
As he tries to grasp his situation, he encounters an injured girl fleeing from a demon king Greol , which he easily defeats. As these are not parts of the original game, Kunai reasons that someone in this world must have tried to summon a real demon lord but accidentally summoned him. Together with the Aku girl they begin to travel together, but there's no way that others will leave a "demon lord" with such overwhelming strengths alone. While being targeted by countries and saints that are trying to subdue the demon lord, they cause turmoil wherever they go.
During a surprise confrontation in the outdoor bath, Angel White finds out Kunai may be more than meets the eye. On their way to the Holy Capital, the party runs into a small village with big problems and decides to take matters into their own hands. Kunai summons one of his underlings who lends Aku a helping hand.