People die, then that's all... or at least, it should be that way. There may be anomalies, yes – the occasional hero of old getting reincarnated for some obscure purpose – but who knows what the gods are thinking. If they are thinking at all. If there are gods, to begin with.
What would explain such a mistake, then? The hero mark wasn't given to our reborn champion, but to his perfectly normal sister. A prank from these mindless gods, perhaps. Luckily for him, he was done with this hero business and had other plans for his new life, so it's all good... Here is the story of one who isn't meant to stand among heroes, kings and emperors anymore, yet will find himself holding power over them.