Clan Penwryn were a Dal Riadan family whose name was brought to Erin by migrating members of the Gryphons faction. The last adult member of the clan was Owain am Penwyrn, who constructed Fort Penwyrn on the border of Dal Riada and Ulster after the Wellspring of Evil corrupted the Dal Riadan peninsula. After his death in battle, Owain's widow Professor Katya Penwryn carried the clan name to the Underdark and there created a house with the blessing of both Kiera na Morna (High Queen of the Dragons) and Barran Ironfounder (Imperator of the Tarantulas).
House Penwryn were instructed to take possession of Fortress City Maermyn under the Albion coastline, and to repair the damage done during the brief but brutal rule of House Eternal. Lady Katya began the work of rebuilding Maermyn's position as a vital part of the Underdark's food production, and complemented that with the construction of libraries and schools designed to impart and enhance the knowledge and skills needed in such a place. She departed the Underdark on a pilgrimage before that work was complete, but is considered by many to still be the Lady of the House.
Although still in its infancy, House Penwryn continues to grow in strength and capability. They are a meritocracy who embrace a more cosmopolitan attitude towards class structure than their neighbours. Appropriately, they are represented by creatures of all races and place a far lower emphasis on the elevation of their Drow compatriots than more traditional houses. The more martial members of House Penwryn honour their celtic heritage on days of great conflict by wearing woad into battle. They are in some cases also cross-pantheonic, worshipping ancestors from both the Tarantulan and Dragon pantheons.