Thunder or Thunderstar is an orange tom with white paws. He is the founder of ThunderClan.
- Thunder is born to Storm in a Twoleg monster nest. When the place is under attack by the monsters, Storm dies and Thunder is the only kit to survive. Gray Wing takes Thunder to his father, Clear Sky, but is told that he cannot care for a kit. On the way back to Gray Wing's camp, he asks why his father hates him and is told that it's complicated. They let him stay and Hawk Swoop agrees to nurse him.