Shesa was a Bajoran who was Kai of Bajor during the time Opaka Sulan was a Prylar. In 2376, seeing how nervous people were around her, Opaka remembered she felt a similar nervousness when she was with Kai Shesa. (DS9 novel: Unity) Given the timeline of the Kais introduced in the Star Trek: Terok Nor series, Shesa may have been the Kai prior to Meressa, or the Kai between Meressa and Arin.