Starts at 6:40 AM (in 38m 12s)
Use hard crowd control to break the Hammer Knights' shields as soon as they appear so damage can continue.
At 75%/50%/25% health you gain a polarity (positive or negative)-follow the prompt to the matching boss to keep stacks aligned and avoid retaliation.
When both bosses reach 25% they regroup in the center; stack together, cleave carefully, and keep breakbars controlled to finish the fight.