Hasskor

 was the leader of the Ice Warriors on Coldstar. He was of the Ice Lord class and was planning a revenge on the humans. His plan was to crash coldstar into the planet. He was part of the Sectarian Cast. He coerced the Tenth Doctor into allowing him into the TARDIS. He explained to the Doctor that the humans burned his world and that's why he wanted revenge. Lorna explained to him that some of his people survived. Knowing that he no longer need to seek revenge, he died but he set his self-destruct mechanism in his suit in order to kill the Doctor. (AUDIO: Cold Vengeance)