you can kill sadha in horror sleep after reaching the consulate without pissing the red prince off if she attacks you when you break the dragon egg/piss off the hatched dragonling. i think that's the case anyway. the fight is significantly easier than the shadow prince's fight. i can't confirm what the red prince's response to this is afterwards though because my quest bugged, so proceed with caution.
also can't say for sure how this affects the end of the game
