Just watching William move around was entrancing to Angelica and her twenty surviving masters, quite terrifying to both the dark masters and monsters.
The first to turn around and run with their tails in their jaws were monsters. They weren't intelligent as humans, but they were ruled by their instincts. And right now, they felt they were standing in front of a predator, one who wasn't on their scale to compete with.
William didn't care about these monsters. His main target was the dark masters. He kept flashing right and left, attacking everyone around without leaving none alive but Edward.
The battle since he joined ended quite fast. He didn't forget to collect the loot, rings and gears, before turning towards the stupefied Angelica and other masters on her side.
"What are you waiting for? Take him down, exert your vengeance and clear a little of rage swelling in your hearts."