Killed by the Bane
Twirltongue was a 'friend' of Pearlpelt (more commonly known as the Bane)'s. However, in reality, Twirltongue was simply using the Bane to achieve her own goal of being the queen of the Gnawers. She is noted for having a beautiful, silvery, well groomed coat of fur. She is also very well known for her persuasive skills. It is stated by Ripred that she convinced him that he was well liked.
Twirltongue first appeared in Book 4 with two of her friends, they were under the city with Gregor, knowing that Ripred taught Gregor echolocation in that spot, and that Ripred wouldn't appear. This is where she nearly convinced Gregor that Ripred was the enemy, however, Gregor managed to realize she was lying and was nearly killed by Twirltongue's friends, but he managed to escape in the nick of time.
Twirltongue also appeared in Book 5. She was feeding lies to the Bane, teaching him how to be a good leader, and that he would reign supreme. She would normally sit on the Bane's enormous back, where she could teach him without moving a muscle. In the final battle of Gregor and Ares and the Bane, where it was revealed that, seemingly, Twirltongue was just trying to get the Bane killed so she could take over. When this was revealed, the Bane lost the last bit of his sanity and shouted, "No, no one will ever follow you again!" And ripped her head clean off, killing her. After killling her, he didn't seem to realize that she was dead ("Where did she go?"). The Bane blamed Gregor for her death.