Arin was a vedek and later kai of the Bajoran faith. In the years leading up to the Cardassian Occupation of Bajor he was a vedek and aide to Kai Meressa until her death in 2325. (TLE - Terok Nor novel: Day of the Vipers) By 2346 he himself had become kai, with an Obsidian Order agent, formerly under the guise as Oralian priest Pasir Letin, now posing as the late Vedek Gar Osen, as his most trusted advisor. When Vedek Opaka began advocating the abolition of the d'jarras he, under pressure from Gar, had her expelled.