Ummmm.... I'm not quite sure if it's the same thing.

[God, where to even start explaining this.]

Soooo... the Emperor has a harem, right? A bunch of queens and empresses, and they all exist in a hierarchy, politically. If and when an Emperor dies, the queen at the top of the hierarchy becomes the new Emperor. It's basically like the spirit of the Emperor changes into a new body once the old one is used up.