Hey I'm looking for a story for my friends, she says the story is about two people tryna f...

Hey I'm looking for a story for my friends, she says the story is about two people tryna fight for the throne but for some reason everytime one wins they both reset back at the start with their memories in intact and basically have to compete again. She doesn't remember if it's novel or a comic, let me know if there's anything similar to this please