Marauders of Darrowshire

I require a rare reagent for the powerful spell I intend to cast: skulls from the scourge who took part in the battle of Darrowshire. Take this crystal and hunt scourge champions for their skulls. The crystal is enchanted; if a champion took part in the battle, then when you pass the crystal over its skull it will resonate. Bring me those resonating skulls. Go, ‹name›. You'll find scourge champions in the Fungal Vale to the north. Go.