Tsireya, nicknamed Reya, is the thirteen-year-old Tsakarem of the Metkayina clan and is the daughter of the clan leaders, Ronal and Tonowari, as well as the younger sister of Aonung.

When Jake Sully and his family came to the Metkayina clan, her father assigned the task of training the Sully children to her. Tsireya, having a calm and welcoming presence, agreed with pleasure. She taught them The Way of Water and how to free-dive. Tsireya formed a good friendship with the family and a close bond