Murder a grove full of refugee teiflings and druids.
Just druids and tieflings...and believe me if you actually take Haslin as a companion you'll wish you'd sided with the goblins when you had the chance. The dude supposedly tells a lot of really disturbing stories very casually about stuff he does with animals while in animal form, at least if Swen is to be believed. You're doing them a favor by helping them out of their misery when siding with the goblins.
