Huntsmans power transfer

River came sailing through the air and landed behind my shield in a crouch to be able to keep his head at the same level as mine. He dropped something messy out of his right hand—the Huntsman’s grey corpse, minus its head. “Look,” he said.
I did. Right before my eyes, the corpse withered and shrank away, deflating as if it had been a skin filled with air. I could sense energy rushing out of it, something moving almost too quickly to be sensed at all.
And the other Huntsmen screamed again, in primal fury. Louder.
“Each that falls gives its strength to its packmates,” River Shoulders snarled. “Quickly!”

Battle Ground Chapter 9, Page 88