Gruul, an armoured giant, was the powerful overlord of the famous Mercenaries of Arn, who fought for the Elder Gods against the Triumvirate during the War of Humanity. He was constantly surrounded by an elite guard of warriors of his own race, known as the Arcanians.
After the War of Humanity ended, Gruul and his men fathered the race of trolls by mating with adventurous human women.
His body is interred in an elaborate tomb far beneath the Mannaseh Swamp in the lost city of Kasmarkin. Discovery of his tomb led to the return of Prospero, the Merchant Lord.
For a time, Gruul assisted with the Trial of Rebirth for new adventurers on the plane of Ceylon by teaching the basics of combat.
His mark on history is imprinted on the Gruul battle figurine.