Find Leviroth in the waters below the iceberg floating among the northern edge of Riplash Ruins. Use the Trident of Naz'jan to slay him and return to Karuk to the north of Riplash Strand.
Raj Naz'jan was the emperor of Riplash when Leviroth was imprisoned. Azshara herself blessed his trident so it would slay the beast should it ever escape.
Now you wield it, <race>. As much as it disgusts me, I will have my revenge on these barbaric giant-men.
Take the trident to the depths beneath Riplash. You will find Leviroth below an iceberg closest to northern Riplash.
Drive the trident into his flesh and slay him! Return to whomever sent you when you're done; I wish to see no more of you.