Gleefully imagining the destruction that he will wreak, Grendel bursts into Heorot. He tears the door from its hinges with his bare hands and immediately devours a Geatish warrior while Beowulf carefully observes. When Grendel reaches out to snatch up Beowulf, he is stunned to find his arm gripped with greater strength than he knew possible. Terrified like a cornered animal, Grendel longs to run back to the safety of the swamplands. He tries to escape, but Beowulf wrestles him down. The combatants crash around the hall, rattling the walls and smashing the mead-benches. Grendel begins to shriek in pain and fear; the sound terrifies all who hear it. Beowulf’s men heroically hack at the demon as Beowulf fights with him, but no weapon on earth is capable of harming Grendel. Beowulf summons even greater strength and rips Grendel’s arm completely out of its socket. Fatally wounded, Grendel slinks back to his swampy home to die. Back in the mead-hall, Beowulf holds up his gory trophy in triumph. He proudly hangs the arm high on the wall of Heorot as proof of his victory.

The following morning, the Danish warriors are amazed at Beowulf’s accomplishment. They race around on horseback in celebration, following the tracks of Grendel’s retreat to the marshes. Beowulf’s renown begins to spread rapidly. A Danish bard sings Beowulf’s story to honor him and also recites the story of Sigemund, a great hero who slew a terrible dragon. The dragon was the guardian of a treasure hoard, which Sigemund won by slaying the dragon. The bard also sings of, and contrasts Beowulf with, Heremod, an evil Danish king who turned against his own people.

Hrothgar enters the mead-hall to see the trophy. He thanks God for finally granting him relief from Grendel. He then praises Beowulf, promises him lavish rewards, and says that he has adopted the warrior in his heart as a son. Beowulf receives Hrothgar’s gratitude with modesty, expressing disappointment that he did not kill Grendel in the hall so that all could have seen the demon’s corpse. The narrator mentions that the trophy arm, which seems to be made of “barbed steel,” has disproved Unferth’s claims of Beowulf’s weakness. Order is restored in Heorot, and all the Danes begin to repair the great hall, which has been almost completely destroyed.

Beowulf is divided into three main parts, each of which centers on the hero’s struggle against a particular monster—first Grendel, then Grendel’s mother, then the dragon. In Beowulf’s bloody battle against Grendel, the first part of the story reaches its climax. The poet chooses to relate much of this struggle from Grendel’s perspective rather than from Beowulf’s, emphasizing the fear and pain that Beowulf inflicts upon the demon. This narrative technique makes Beowulf seem even more godlike; he seems to be an unstoppable heroic force. Throughout the fight, Beowulf is treated as more than human. He shows himself stronger and more powerful than even the monstrous Grendel, and he seems completely invulnerable. It is never entirely clear what kind of being Grendel actually is—he is described as a demon, fiend, spirit, and stranger (in the Middle Ages, the word “monster” was used to describe birth defects; Grendel is later referred to as “an unnatural birth” [1353]). In any case, he seems to be a horrific beast, a large and distorted creature of vaguely human shape. His supernatural monstrousness makes Beowulf’s conquest of him all the more impressive.

Many readers believe that each of the three monsters in the book has a symbolic or allegorical significance. The narrator seems to present Grendel as a representation of evil in the abstract. He can also, however, be interpreted as an evil force lurking within the Danish society itself. The theological implications of his descent from Cain support such an interpretation. The Old Testament relates how God punished Cain for his murder of his brother Abel by cursing him to wander. Grendel, too, is cursed and wanders, “haunting the marches, marauding round the heath / and the desolate fens” (103–104). The “marches” are the borders, and in Old English Grendel is called a “mearc-stapa,” or border-stepper (103). The poet’s culture finds the borders of society threatening, and Grendel is presented as an outsider who has penetrated the boundaries. Since Hrothgar, like Grendel, established himself by conquering his neighbors, some critics see the marauding Grendel as the embodiment of the society’s own sin come back to haunt it. The nature of his abode—a swampy, dark, womblike landscape—supports this interpretation. He seems to be an incarnation of evil created by the human conscience. Furthermore, it is important to note that Grendel and Beowulf forego weapons to engage in ferocious hand-to-hand combat. This clash is not a mere battle in a culture dominated by warfare but rather a more personal, primal conflict between equal, opposite forces.

The Beowulf poet’s description of the scop, or “bard,” who sings Beowulf’s praises after the defeat of Grendel shows that he clearly values good workmanship, both in objects and in poetry. The narrator emphasizes the craftsmanship of the bard’s “well-fashioned lines,” just as he tends to dwell on the skill with which weapons and armor are forged. The bard’s stories of Sigemund and Heremod reflect on the greatness of Beowulf by comparison and contrast, respectively. The Sigemund episode relates a familiar story from Norse mythology, which foreshadows Beowulf’s fight with the dragon in the third part of the epic. The evil king Heremod, who fails to fulfill the responsibilities of a lord to his people, represents Beowulf’s opposite. By comparing Beowulf to a king, the scop anticipates Beowulf’s destiny for the throne in Geatland.

Heremod also serves as a foil for Hrothgar. Hrothgar’s speech on the morning after the combat attributes Beowulf’s victory to God without detracting from Beowulf’s personal glory. He feels himself to be bound in a “new connection” with Beowulf by this great act of service. His appreciation and dedication to Beowulf are manifest in his promises that Beowulf will have the honors and rewards that are the appropriate recompenses for faithful service to a powerful lord. Unlike Heremod, Hrothgar represents the dutiful ruler in every way. Consequently, the Danes’ loyalty to Hrothgar doesn’t abate even when they are celebrating and revering Beowulf: “there was no laying of blame on their lord, / the noble Hrothgar; he was a good king” (861–862).