This was always an issue in Rome. People were afraid their heirs would turn out to secretly be wannabe dictators, and you couldn’t do anything about it since you were dead. How would you go about making sure your heir was as close to your vision as possible, both outwardly and in their desires should they be emperor?
Genetically engineer like 20 of them and hope one turns out good after being stolen by Tzeentch and half betray you because you were a bad dad