In this epic poem, as in many of the classic epics, good and evil are clearly defined. Though the poem was composed and transmitted orally for many years in the pre-Christian era, once it was written down, Beowulf grew to contain numerous references to Christian theology, including gratitude for and reliance on a single God. For example, when Hrothgar first sees Grendel’s arm hanging in Heorot he comments, “First and foremost, let the Almighty Father / be thanked for this sight” (lines 927-928). He expresses gratitude to one higher power before even acknowledging the prowess of his hero. After Beowulf defeats Grendel, the poet asserts that “Past and present, God’s will prevails” (1057). This line implies that God was on the side of Hrothgar and Beowulf, which is also supported by early descriptions of Hrothgar being protected by God, and by the introduction of Grendel himself. The poet writes, “he had dwelt for a time / in misery among the banished monsters, / Cain’s clan, whom the Creator had outlawed / and condemned as outcasts. For the killing of Abel / the Eternal Lord had exacted a price: / Cain got no good from committing that murder / because the Almighty made him anathema” (104-110). Grendel is hated by God, punished for killing his brother Abel, in the Old Testament story of the two sons of Adam and Eve. The description implies that Grendel is an enemy of God, and as such, God will side with the righteous Hrothgar and with Beowulf in their justified battle with the “fiend out of hell” (100). 

The clear distinction between hero and villain is seen again in the fight between Beowulf and Grendel’s mother. The latter is described as “that swamp-thing from hell” (1518), and even though Beowulf’s weapon fails against the monster, a magical sword appears on the wall. Again, “holy God / decided the victory” as He “redress[ed] the balance / once Beowulf got back up” (155-1557). It is at this moment that Beowulf spies the giant sword that only he can lift and swing. God has determined that Beowulf is fighting for what is right, good, and just, and God helps Beowulf to victory. Finally, the dragon that eventually ends Beowulf’s life is said to guard a “heathen trove,” which implies the dragon is also an enemy of God. When Beowulf begins to lose in his conflict with the dragon, he worries that he has offended God, but the poet asserts that it is Beowulf’s fate to die on this day. The rhetoric around Beowulf’s final battle combines Christian and pagan beliefs, but the poet leaves no doubt as to who is the hero and who the villain in this or any other fight in the poem.