The Mountain’s reputation as a warrior is built on his physical dominance and lack of mercy. Serving as a knight and enforcer for the Lannisters, he carries out their dirtiest work, from brutal executions to battlefield carnage. His most infamous act comes during Robert’s Rebellion, where he brutally murdered Elia Martell and her children on Tywin’s orders, an atrocity that fuels Oberyn Martell’s quest for vengeance years later. Gregor’s unyielding loyalty to the Lannisters, combined with his terrifying presence, makes him a key instrument in their political machinations.