Sauron is an external cross-reference. Any reader of fantasy will know who's being referenced. The original idea came from books like LotR where there's a super-powerful, evil antagonist whose backstory is that they've always been so powerful and evil. It makes no sense. So, I set out to figure out how such an antagonist would come to be.
The book pitch, unfortunately, doesn't work. A key element of the worldbuilding/story is that the Heir must be named. (It's a position for life; their own or whomever they will inherit from.) If they aren't named, there is no Heir; no automatic fallback. I'll have to look at it from a completely different angle to get something that works better.