Sissy

Sissy is one of the few humans left at the Heper Institute. She is the sister of Ben, and it is said in The Prey that she was named Sissy to help Ben remember that she's his sister. After the previous hunt, where their parents were killed, Sissy took the leader role and has since then lived alone under the dome along with Epap and Ben. Sissy cares deeply for her brother and Epap, and later on cares for Gene after he joins them.