I've seduced the spouse of a powerful ruler and this resulted in a child. The ruler thinks the child is his and the offspring is of his dynasty.
How do I benefit? Is there any way I can actually profit from putting my illegitimate child on the throne? Can I somehow tell that he's mine once he inherited, legitimize him and he becomes of my dynasty? Can he be of my bastard-dynasty and be easier to ally with? Is there actually any use in this accomplishment, except 'for the fun of it'?