Diyah the Silvertongued

Diyah the Silvertongued, Rider of the Storm, Gloomslayer, Archimandrate of the Ascent, Mistress of the Left-Hand Spiral and Guardian of the Fathomless Vertex
Diyah the Silvertongued is unique amongst the Archdevils in that she was not raised from the lower ranks of Devils, but was rather a succubus - technically a Loth, a Fiend unaligned with the Nine Hells or the Pits, but serving either side as suited her.
Her status changed when she was persuaded to join forces with Astolat the Bloodbane, another outsider to the infernal hierarchy, to slay the Abyssborn master of Escharon, Ixis Gloomshrouded, and forge its bones into the Fathomless Vertex. This feat saw her accepted as an Archdevil, and she was granted the spear Mareth, forged by Fulmar the Doomhammer.
Diyah has the form of a succubus, that of a beautiful, usually female, humanoid, with slender horns rising from her brow, and four, batlike wings on which she navigates the tempests of Escharon with unparalleled skill. Unlike most succubi, she goes armoured, for hers is a domain at war, and gleaming selenite mail lends her an almost angelic air. A coronet of red gold rests between her horns, studded with rubies which burn with their own, internal flame.