How does Beowulf kill Grendel?

Beowulf kills Grendel by tearing off his arm at the shoulder. The fight takes place inside Heorot, where Beowulf confronts the monster without a sword or other weapon.

Grendel has long been able to slaughter Hrothgar’s warriors because ordinary weapons cannot harm him. Beowulf therefore relies on his exceptional physical strength and meets the monster in hand-to-hand combat. When Grendel tries to escape, Beowulf holds on and rips away the entire limb.

The injury is fatal. Grendel flees from Heorot toward his lair in the marshes, leaving a trail of blood, and dies there. Beowulf and the Danes display the arm in the hall as evidence that the terror haunting them has been defeated.

This victory does not end the danger completely. Grendel’s mother attacks Heorot the following night to avenge her son and retrieves the severed arm. Beowulf must then travel to her underwater lair, where he kills her with a giant-forged sword. The sword is used against Grendel’s mother, not Grendel.