There were thought to be multiple universes, all with different scenarios. Some of them are completely different, while others are similar yet not. Nagumo Hajime was someone who had been traveling to and from different worlds thanks to his experience in another world called 'Tortus'. To be more accurate, he was kidnapped by a false god named Ehitto, along with his other classmates. Although he only acquired the simple common job as a synergist, he still worked hard to achieve victory. While he was trapped in that world, he had a myriad of different experiences. While some are good, he also suffered from bad experiences as well. This experience had him acquired lost powers that existed in the age of the gods. He also acquired a lot of companions along his journey. After a lot of tragic events, finally he managed to annihilate the false god and returned home along with his other companions. This experience grant him power and entitled him to be a god slaying demon king. He is the worlds strongest, even though he had a common occupation.
Peace had risen after the fall of the false god, and Nagumo Hajime spent the rest of his life at peace with his 7 wives and daughter and the rest of his family. And such Hajime is currently doing grocery shopping at the nearby convenience store. During his way back he sensed some kind of distortion.
"Hm?... What was that?"
Before he could react space distorts around him and sends him through another world.