The first hero that spotted him shouted, "It is the mind fire villain."
This drew everyone's attention and gave them a viable target to expel their anger against. But they didn't attack randomly. They had a plan they had prepared just for him.
They hadn't been able to use this plan for the past two days. So they were very eager to show what they were capable of. The fact the Count is dead also gave the determination to win.
They put that plan into action now. All of them closed their eyes while relying on the hero with mental coordination to provide them with information about their environment.
The hero with the mental coordination ability was standing still as he used the mental connection he had made with everyone to coordinate them.
He was taking visual and other perception information from the heroes with echolocation and olfaction positioning ability and then passing it along to the other heroes who had become blind.