Equilibrium+ with either deshell, deprotect, imperil, curse, slow and a guard of your choice. If you want it to damage properly you can give it a deprotect chaser from one of the spells and a weapon like double diety so it serves a decent purpose. As a shield the ones in the wildland research give up to 40/45% atb speed so you'd want one of those.
It can tank, debuff and damage while keeping the stagger bar up. Personally I just stopped using guard eventually, so I could place a third debuff.