Children of the Lamp: #4 Day of the Djinn Warrior by P,B Kerr
John and Philippa Gaunt are twins with a magical difference...They have ancient djinn power, but can the Children of the Lamp outwit Iblis? He has woken the warriors of a long-dead emperor from their sleep, and thirsts for revenge...This is the fourth djinn-credible adventure for the Children of the Lamp.