If you use a weapon in a grid that is the favored weapon of a Hime in your team, she gains additional 20% of the weapons stats as bonus. It is a min-maxing-option if you want to absolutly optimize.
so if a weapon gives 100hp n 1000atk, if its hime favorite weapon she would get 120hp n 1200atk. if so that's pretty neat. thx ito fa the info and quick reply.