When Firescar saw the ring you got from Kerubar, she told you the ring was hers--a gift from her love. Firescar got sick while waiting for Thersites to return from Sanctum. She asked you to deliver a message to break up with him to save him from her illness. You went to Thersites in Sanctum, delivered her words and the ring. Thersites couldn't remember her at first, but when he did remembered, he agreed.