but the naugrim made a circle about him when he assailed them , and even his mighty armour was not full proof against the blows of their great axes ; and when in his rage glaurung turned and struck down azaghal , lord of belegost , and crawled over him , with his last stroke azaghal drove a knife into his belly , and so wounded him that he fled the field , and the beasts of angband in dismay followed after him .