Halftail is a big, broad-shouldered, dark brown tabby tom with patchy fur, yellow eyes, and part of his tail missing.

Halftail was a ThunderClan elder under Bluestar's leadership in the forest territories and previously served as a warrior under Pinestar and Sunstar. Originally named Sparrowpelt, he mentored Snowfur and Redtail and became mates with One-eye, having two kits, Mousekit and Runningkit. After losing half of his tail from a badger, Sparrowpelt's name was changed to Halftail, eventually retiring to the elder's den. Halftail, along with the other elders, were worried about Fireheart's unorthodox deputyship, and following a fire that ravaged through ThunderClan's camp, Halftail was trapped. However, despite Yellowfang's best efforts to save him, he succumbed to smoke inhalation and ascended to StarClan.