Saga of Tanya the Evil (2017)

S1E2 Prologue

Tanya's true origin comes to light: in a past life, she was a detached Japanese salaryman, shoved in front of a train by a worker he had fired. A wrathful entity known as Being X then cast him into another world, reborn as an infant girl—with no guarantee of another life after this one. Now Tanya must fight to stay alive, because this existence is all she has.