What rat is the antagonist of Gregor the overlander?

The antagonist of "Gregor the Overlander" is a giant rat named Ripred. He is a cunning and fierce character who initially poses a significant threat to Gregor and his companions. Ripred's complex personality adds depth to the story, as he ultimately becomes a key ally in the fight against greater dangers in the Underland. His motivations and actions challenge Gregor's understanding of good and evil throughout the narrative.