Quote Originally Posted by Divine Wind
Plus if you want to keep that bloodline pure, accidently send those dim witted sons or brothers to invade Islands on there own, where they stand no possible chance of victory.

Or your sons survive their suicide missions--er, I mean "glorious battles"--and actually start to develop some good traits. I've had a number of useless heirs become worth something after they've gone through a few battles they were never meant to survive.