The Master (first portrayed by Roger Delgado, whom many fans consider the best) was first introduced during the Third Doctor's reign. Although he has had dealings with most incarnations of the Doctor since (the First and Second via comic and prose, and he has had no direct dealings with the War or Ninth Doctor at all), it was with the Third whom many of his major battles took place. No matter how many times he was thought to be defeated for good, he would always find a way to return.