Rin Tsukishima (築島 倫 Tsukishima Rin) is a normal high-school student studying in Saikai Academy who is the classmate of Kojou Akatsuki, Motoki Yaze and Asagi Aiba. She is a close friend of Asagi along with Motoki.
Rin has short dark brown hair and brown eyes. She wears the Saikai Academy high-school uniform.
- The name Rin means "dignified, severe, cold" (凛).
- Rin's surname Tsukishima means "moon" (月) (tsuki) and "island" (島) (shima).