I have had a story idea of a similar time travel concept (with a fake evil person) where each chapter is basically "Ok, thenworld is ending, but we will time travel and stop this despot.". Then they send say, a woman back. Next chapter, "Ghe world is ending, we shall send someone back to stop this despot and his wife, "him, his wife, and his manservant, "hum, his wife, and his respected general, and his manservant."

You get the idea. Basically, everytime travel goes back and gets seduced into helping the evil guy, and each new timeline is unaware of previous attempts, but the historical records mentions "new people".