Saru's sister on Kaminar, a village priest who stayed behind when he left to join Starfleet.
Siranna is Saru's sister on Kaminar, where the Kelpiens long lived as prey for the Ba'ul. When Saru built a device to contact the stars and left the planet with Philippa Georgiou to join Starfleet, Siranna and their father Aradar remained in the village, where she served as a priest.
She met her brother again when Discovery came to Kaminar after Saru survived the vahar'ai, the biological change Kelpiens had been taught meant death. Though hurt that he had left, she joined him as Kelpiens and Ba'ul came to a new balance on their world.