How does Grendel die in Beowulf?
Beowulf and his men await Grendel in Heorot Hall, which is empty because Grendel has been terrorizing it. At night, Grendel strikes. Beowulf pretends to be asleep, but when Grendel attacks, Beowulf jumps up and grabs his claw. A fierce battle between the two follows, with Beowulf fighting Grendel barehanded. Beowulf's men try to attack and kill Grendel with their swords, but Grendel has put a spell on their weapons. None of their swords are able to penetrate Grendel's flesh. Beowulf is finally able to wrench Grendel's arm out of its socket at the shoulder. This mortally wounds Grendel, and he runs off to die. The claw, arm, and shoulder of Grendel are hung in Heorot Hall, and a great celebration follows.
At night, Beowulf and his men lie in wait for Grendel in Hrothgar's Mead Hall. When Grendel invades the hall, he kills and eats two of Beowulf's men, which gives him a false sense of security. As he reaches for his third vicitm, Beowulf, he is shocked to discover that his claw is being bent backward causing him immense pain. Their battle concludes with Beowulf's ripping Grendel's arm off, fulfilling his promise to Hrothgar to kill the monster with his bare hands. Beowulf nails Grendel's severed arm to the mead hall rafters and, although Grendel runs away, he is later found to have bled to death in his underwater lair.
Beowulf kills Grendel in a great battle, and as proof of his conquest, hangs the monster's arm and claw over the rafters of Hrothgar's Great Hall. Grendel had terrorized the kingdom for a dozen years and killed many, many warriors. There is no sympathy for the monster and his defeat cements Beowulf's reputations as the greatest of the great.
Although the answer is never presented clearly, Grendel appears to die as a result of blood loss. Beowulf fatally injures Grendel in the meadhall and the beast skulks home to its mother to die.