Red Temple Diocese
Judging by the title "the Flametruth, the Light of Wisdom, and First Servant of the Lord of Light", and that Volantis possesses the largest following of the Lord of Light in Essos, it seems that Kinvara may be the equivalent of a metropolitan bishop/archbishop, assuming that there's a definitive hierarchy among the various red temples in the Free Cities.
In Season Three, Melisandre reminded Thoros of Myr that the "High Priest" ordered him to make a convert out of Robert Baratheon. It was not specified if this high priest presided over the Red Temple in Myr, or if he held higher authority. --Fenrir51 (talk) 17:59, May 17, 2016 (UTC)