They're about as durable as the average human! However, their chitin armor makes it more difficult to get a direct hit when they're moving in the ash. But if we're talking about an upset boar, that boar will win, hands down.

Arrival of the other Ash Sharks depend on two factors: blood or another Ash shark's cry. If they don't cry out, it will take at least five minutes for one to arrive. With blood, it will take about two minutes. With cry, thirty seconds, and cry and blood takes about, twenty seconds.

But yes they will focus on the injured, preferably bloody Ash Shark then someone uninjured.