Stun the mob to break the shield. The following moves have stun: - Yuan Ye CUB attack skill (given for free at Commandant Rank 80) - Kamui Bastion QTE - Kamui Bastion blue orb - Kamui Tenebrion blue orb (must be in signature Dark Form) - Roland Flambeau double yellow orb (single yellow orb if in signature Apex of Trickery) If you don't have any of the above, you'll need to brute force it and just keep attacking it. Use the shield phase to build up orbs and form 3pings, then spend them when the shield goes down.