The fight follows four quick steps. First, Beowulf gets his bearings and wrenches free from her grip to take a stab at the mother with Unferth’s sword. Second, the sword failing, he flings it aside and tries to wrestle as he had grappled with Grendel, but he trips and falls. Third, Grendel’s mother does not play by the rules but pulls a knife on him, which his chain-mail shirt succeeds in keeping out. Fourth, Beowulf tries a new approach by taking a sword from the wall and bringing it down on her neck. This fourth phase ends the fight with her death.
Why did the second sword succeed where Unferth’s sword did not? The poem provides the answer that the second sword was older and larger. But the sword is not only older, it is more supernatural, fit to kill a supernatural being. Moreover, an ancient sword might also be made of bronze, not iron, and if Grendel’s mother is charmed against only iron, then she would suddenly be helpless. The sword Hrunting apparently bounced off her head, while this one slices right into the bone. It is a giant’s sword, such as only Beowulf could lift. These are not the Frost Giants of Norse legend, but the human giants of early Genesis, before the flood. The sword may have some power of its own, perhaps made to kill Cain’s kin but failing in its first try as its owner perished. Having waited patiently many centuries on the wall for a hero to come, the sword now fulfills its purpose. The poem does not tell such a story directly, but in evoking the age of heroes and giants before the Flood, it suggests some sort of magical past.
The magical giant’s sword is able to do one more task before it fails. Beowulf now cuts off the head of Grendel, although Grendel is already dead. If Beowulf had not found Grendel and taken his chance to cut off the head, perhaps Grendel’s undead body would have taken to roaming the land again, causing ruin and death. Icelandic stories of such zombies, called draugrs, make clear that the remedy is to cut off the head. As a further reason, many people survive wounds of all sorts, but the loss of a head is sufficient proof of death. There are parallels in the Bible of such trophy heads, in the stories of Goliath and of John the Baptist. In the same manuscript binding with Beowulf is the story of Judith, a courageous widow who beheads Holofernes, the Babylonian commander. Clearly, there is no better death certificate than a severed head.
Two beheadings in the underwater hall create a new upwelling of the supernatural blood. Like a water jet in a hot tub, the blood bubbles up to the surface. This sudden rush of blood occasions a mistake, in which the wisdom of man fails. Hrothgar’s counselors see it and these old men, who know too well the ways of the world, are unanimous that the blood can only be that of Beowulf. In a world where men meet death, where Fate will bring about sudden reversals of fortune, their “wisdom” is understandable. Perhaps Hrothgar is growing tired, for the decision is made to abandon the mere and go home. Only the Geats remain.
The magical natures of both the sword and the blood come together in the vivid image of the sword blade melting. Like “battle-icicles,” the sword melts “like ice when the Father loosens the frost’s fetters, unwraps the water’s bonds” (1606-10). The stated reason is the heat of the monsters’ blood, which the metal cannot stand, but clearly there is a supernatural principle at work. The sword has done its duty and the blade now melts; perhaps the monster’s blood takes a last revenge on the blade that spilled it. Beowulf would be well within his rights to take other treasures from the hall but, perhaps unnerved by the melting sword, he decides that the weapons and treasures are not to be touched. With three possessions — Hrunting, the giant sword hilt, and Grendel’s head — he is ready to swim to the surface.