I might use my wind team on her, since it can reach 50% atk down.

Joan with black propaganda or sniper shoot or ambush. Whatever I feel is more useful.
Gaia.
Zephyrus.
Cybele.
And maybe Belobog just in case her ailment removal might be useful. Or Satan for her orb drain and def debuff. Or Balor for... all debuffs that she have?
as for sub slot:
Heimdallr
Hermes