Irene Radford 
Guardian of the Trust [EPUB ebook] 

The quest for peace and protection in Britain has passed down from the Merlin and Arthur the Pendragon to the sole survivor, Resmiranda Griffin. Raised in the Christian tradition, she refuses to acknowledge her magical talents or the existence of helpful fairies, until dark forces force her into the complex politics, both mundane and magical, that divides England from their lawful king, John Plantagenet.Inspired by a demon, her distant cousin Radburn Blakely whispers divisive advice into John’s ear. Only Resmiranda can counter this darkness and lead England to what will create peace between a fearful king and his power-mad barons: The Magna Carta.