She developed a deep bond with Peri that the two likened to sisterhood. In the relationship, Peri often played the role of the "older" sister, since Erimem was only 17 or younger when she started travelling with the Doctor. (PROSE: Blood and Hope) Peri often served as a kind of bridge between Erimem's ancient past and the more modern world inhabited by the Doctor. Nevertheless, Erimem was strong-willed and often showed a wisdom that belied her youth, and a grasp of universal truths that made up for her inexperience with technology.