Gruolun is a character from Spellforce: The Breath of Winter. He's involved in "The three magicians" quest.
Though is wasn't stated in game, but Gruolun was chained by Kithars at the unknown period of time before the rune warrior came to the Stormcleaver Rocks. His past is unknown as well, exept his relations with two other mages, Reyna and Zolowin.
Gruolun is a black mage and he was caught by Kithars by some reason along with his rival mages, Renya and Zolowin. The rune warrior can free him in order to start a quest.