Grumlok is an Orc Warboss, and is joint leader of the Bloody Sun Boyz with the Goblin Shaman Gazbag. Together they control the Greenskin army in the Age of Reckoning. He carries an amulet which massively enhances his natural strength, allowing him to dominate the Greenskin tribes in the Badlands to create a huge Waaagh! which was able to attack and conquer the Dwarf stronghold of Karak Eight Peaks. He and Gazbag are said to be inseparable.

Grumlok was a powerful warlord in any sense, but still hindered by his own nature and driven by instinct to destroy all foes around him instead of being able to concentrate his forces and power on one single goal. This changed forever when he was kidnapped and taken to the court of Malekith the Witch king and given his enchanted amulet. Where he was merely strong before, even for an orc, he was now undefeatable and near invulnerable, and his companion, the shaman Gazbag was now an unstoppable channel of the power of Waagh! With these tools he was put into his place in Malekith's plan to occupy the Dwarfs. Mentally controlled by Malekith, Grumlok and Gazbag set out to unite the Greenskin tribes and destroy their ancient stunted enemies once and for all.

WAR Army Leaders (Kings)
Karl Franz • Thorgrim Grudgebearer • Finubar the Seafarer Tchar'zanek • Grumlok and Gazbag • Malekith