Sarkoth, Hoarder of Treasure, is a unique Quill Fiend found in the Dank Cellar. It apparently leads a group of Quill Fiends that looted the entire cellar. In combat, it does not have any special affixes.
Upon death, Sarkoth and its minions drop additional gold.
Trivia
This mob is most probably named after a forum user to the World of Warcraft Beta, Darkoth. An elite mob from World of Warcraft "Sarkoth" shares a similar name.
Before it was nerfed, this mob was one of the most popular farming spots in game, due to easy access and large gold reward.
A unique scorpion of the same name exists in World of Warcraft.