These big shots are actually all me

I transmigrated into another world. A backward world with no magic, no battle aura, not even electricity. And, of course, I started as an orphan. Fortunately, transmigration did give me one small consolation. Every time I slept, I experienced different lives within my dreams. Lives straight out of myth and fantasy. In one dream, I was one of the ancient gods who led the great rebellion against the Primordial Creator. In another, I became the most powerful grand duke of an ancient empire, the very founder of the nation that would one day rule the continent. In another, I was the greatest hero of the mythological age, the nightmare feared by every evil existence beneath the heavens. In another, I stood as the King of the Elves, the oldest ruler beneath the Twin Sacred Trees. And in one particular dream… I became a girl's god. Only to play the cruelest joke imaginable on her.