Huum tells me you've figured out how to summon the Abyssal Dukes! That's quite an accomplishment.
You know what else would be quite the accomplishment? Smashing up one of those things really good. That'll cause an impression on their underlings, if you know what I mean. Bring back its signet as proof of the deed.
Tavoite
Bring the Abyssal Signet to Bor Wildmane in Cenarion Hold.