All varls are inherently strongly pyrophobic. Yet in the ending, when we see Iver mourning for either Rook or Alette, he has a burning torch in his hand, ready to set their funeral boat ablaze. He is that affected by his or her death.
The Dredge slingers that show up are new to this invasion; even veteran varl haven't seen them before. This is because these are the Dredge women; the Dredge are fleeing with everyone. It wouldn't be too big a deal, there are plenty of female fighters, mostly archers, that are killed in the game. But those sashes that they all wear? Those are slings for Dredge babies. You've been killing women and children for most of the game, unwittingly.