Biriel serves both Asmodeus and Magoth. Mathers’ translation of the Sacred Magic of Abramelin the Mage, says his name means “stronghold of God.” While servitude to Asmodeus and Magoth is mention in other Abramelin material this demon is unique to the Mathers translation. .A.G.H.
Belanger, Michelle. The Dictionary of Demon: Names of the Damneds. Llewellen Publications. 2010. ebook.