[The reference Dean has for that is too far in his own past, and not that complete: Sam never believed everyone could be saved, not on the supernatural side of the coin. He just wanted to save some of them. Dean had fought him on it, capable of optimism only insofar as it applied to those directly around him; in the end, though, he's practical. Too practical for most people to stomach, especially now.

The hunter nods, but misses the way Stiles reacts. He's rubbing the bridge of his nose, trying to think.]

You said he was shot full of arrows. What were they made of? How many, and where did they hit?

What finally stopped him?