Khawarij were the renegades within Islam. 14th century Muslim Ismail ibn Kathir who wrote, "If they ever gained strength, they would surely corrupt the whole of the Earth, Iraq and Shaam – they would not leave a baby, male or female, neither a man or a woman, because as far as they are concerned the people have caused corruption, a corruption that cannot be rectified except by mass killing."[5]Wikipedia Sounds like Isis. Renegade also means a Christian or Jew who converts to Islam.