Debuffing Corrin (F)

My FCorrin:
Dark Breath+(Spd)
Swap/Reposition
Bonfire
Fury
Vantage

Vantage is not amazing with her attack, but the Debuff of DarkBreath+ refined activates after she attacks on combat, even if Corrin dies during the fight, so except for enemies that she can't counter, after all combats she will debuff the enemy Atk/Spd by 7.
It's working perfectly to me!