The White Sakura is a Hardmode summoning weapon which is an upgraded version of the Blue Sakura staff. It will summon a White Wind that will fight for you.
Its best Modifier is Ruthless. The Mythical modifier provides the widest array of stats bonuses, but these primarily affect the initial summon rather than the resulting minion. Additionally, Minions cannot deal Critical hits. The only significant advantage a Mythical White Sakura has over a Ruthless one is knockback.