I like Murtagh's horse.
According to the IC wiki:
Tornac was Murtagh's gray warhorse. Tornac was given as a gift to Murtagh when he was a foal. His namesake was Murtagh's faithful servant, Tornac, who was killed while attempting to escape Urû'baen with Murtagh. The books never mentioned what breed Tornac was, but it was probably a mix between a draft and a warmblood. Tornac was a very important and reliable friend for Murtagh. Tornac's fate is unknown, as the last we heard of him was that he was in a stable in Tronjheim and Murtagh had no chance to retrieve him after the ambush by the Urgals which the Twins organized. Christopher Paolini has stated that he was probably given to another member of the Varden.