Durza

Arya looked sad. But Murtagh crowed, “We won! It was incredible! When the Shade’s spirits—if that’s what they were—flew across Farthen Dûr, the Urgals ceased fighting to watch them go. It was as though they were released from a spell then, because their clans suddenly turned and attacked each other. Their entire army disintegrated within minutes. We routed them after that!”

Eragon, Chapter: The mourning Sage

“Aye, Lady Nightstalker. He promised us good land if we killed his enemies. He tricked us, though. His flame-haired shaman, Durza, bent the minds of our war chiefs and forced our tribes to work together, as is not our way. When we learned this in the dwarves’ hollow mountain, the Herndall, the dams who rule us, sent my brood mate to Galbatorix to ask why he used us so.” Garzhvog shook his ponderous head. “She did not return. Our finest rams died for Galbatorix, then he abandoned us like a broken sword. He isdrajl and snake-tongued and a lack-horned betrayer. Lady Nightstalker, we are fewer now, but we will fight with you if you let us.”

Eldest, Chapter: The Burning Plains, pg 908