That time I got Isekai'd as a Demigod for the amusement of bored celestial entities.

Higher powers get very bored, very easily, and with the power to craft worlds as simply as mortals make pasta, Eternity can get tedious. To pass the eons, Gods have been known to select mortals and arrange for an "accident" that causes them to be dropped in a different world. Sometimes the mortal is reborn as an infant, or awakens at a certain age, sometimes a situation forces high level mages to summon an outsider, and sometimes, just sometimes, these all powerful, all seeing, molders and shapers of universes have.... oopsies. Or, at least, that's what they tell us. But mostly, it's just boredom.