Not sure if more people are suffering with this, but every campaign I start using a custom character from the ruler designer I end up having my sucessors killed pretty fast. I tried everything I always do after a sucession (I place a skilled Spymaster that loves me to disrupt schemes, get rid of courtiers that hate me, distribute gifts to nobles etc), but it doesnt seems to work with the sons of a custom character. Sometimes I even get game over after all my sons are killed in a couple of months after my start character dies. Advices?