Use the Gift of Naias near the Altar of Naias to summon the water elemental Naias. Defeat him and return to Nemeth Hawkeye at Grom'gol Base Camp with the Heart of Naias.
So this Naias is the mastermind behind the Bloodscalp and their exotic magic? I'll admit, this is the last place I expected my inquiry to lead, but no matter, our findings may still prove useful.
Off the coast to the northwest is an island inhabited by lesser water elementals. There's a crude stone slab there that might serve as an altar for the likes of the trolls. Take the totem you found to that altar. Let's see if we can draw this Naias out and distill his power into a more agreeable form.