The Duke of Shards

The Duke of Shards <Abyssal Council> is a level 62 elite named mountain giant, and one of the Elemental Nobles of the Abyssal Council. The Cenarion Circle believe that he and and the other three Dukes are the primary force behind the organization of the Twilight's Hammer Cultists in Silithus.

Summoning

The Duke of Shards does not appear normally in the standard plane of existence but must be summoned. There are two ways of summoning the Duke:

Acquire a set of Twilight Trappings and a [Twilight Cultist Medallion of Station]. This will make you appear to be a middle-ranked leader of the Twilight's Hammer. Travel to a Wind stone and use it to summon a Duke. You have a 1 in 4 chance of summoning the Duke of Shards.
Turn in Encrypted Twilight Texts to Hermit Ortell. He will then mail you a random item. If you get a Scroll: Create Signet of Beckoning (Earth), you can combine that with a [Dark Rune] and 5 [Dense Stone] to create a Signet of Beckoning: Earth. This signet can be used to specifically summon the Duke of Shards.