Saeko Shinohara (篠原 佐恵子,Shinohara Saeko) is Tomoko's best friend who lives with her big brother, an archaeologist.
After the Akatsuki incident, she was traumatized to the point of being unable to interact with anything. But when she hear of the false legend of Sandouko Lake, she began to scuba dive for relics of the Jomon era that tell of an ancient civilization which worshipped an ancient Agito. To keep Saeko in that state of mind, her brother dumped the relics she found into the lake. When her special ability began to surface, Equus Dies attacks her. But during the fight between Gills and Dies, Saeko gets her leg stuck to seaweed and drowns.