A Deer Amongst Eagles

Everyone knows House Goneril. Holst, the famous Leicester General. Hilda, the lovable but lazy daughter. But, there is a third child in the family. Harlyn, the youngest in the family, a swordsman and thinker. What kind of changes could another pink haired Crestbearer make to Fodlan, especially one who catches the eye of the future Emperor herself? T for now, possibly M later.