Sunstar is introduced as Sunfall, the deputy of ThunderClan. After Stonepelt retires, Sunfall is Bluepaw's new mentor. After Pinestar left to become a kittypet, Sunfall becomes Sunstar. The first warriors he appointed were Lionheart and Goldenflower. He makes Tawnyspots his deputy. After Tawnyspots retires to sickness, Sunstar has two options for the new deputy: Thistleclaw or Bluefur. He dosen't know that Bluefur gave her kits to Oakheart, so he makes her deputy, making Thistleclaw furious, same with Tigerclaw. He is later killed by a loose dog. His father and mother are unknown, but his brother is Featherwhisker.