¶ … Old English poem Beowulf offers a number of contrasts in telling the story of the hero Beowulf and his fight to save a community not his own first from the monster Grendel and then from Grendel's mother. Later in the poem, Beowulf also fights a dragon. These monsters fight from different motives, from the relatively petty pique of Grendel to the desire for vengeance from Grendel's mother and the desire for revenge against a wrong from the dragon. In each case, the attack produces a response from Beowulf that shows aspects of his character, makes it possible for him to show his prowess, and suggests the values that shape the society of his time. The monster Grendel attacks Hrothgar's army in Heorot, and the motivations given in the poem begin with the fact that the creature is simply unhappy and does not like to see human beings happy. The army celebrates because of its great victory in war and because Hrothgar has constructed Heorot, and Hrothgar now holds a feast where he gives out rings and treasure to his men. Grendel is described as a "fierce spirit" (3) who painfully endures hardship and "who dwelt in the darkness" (3), and the reason given for his pain is that "every day he heard loud mirth in the hall" (3). The warriors "lived in joy" (3), while Grendel is called a "grim spirit" and a "hellish enemy" (3). Grendel is also described as an "Unhappy creature" (3), and one of the reasons for this is that "he lived for a time in the home of the monsters' race" (3). This is a reference to the place to which Cain and his progeny were banished after Cain slew Abel. This aspect of the story is a likely addition from the Christian era, but the story as it now stands suggests that Grendel is seeking revenge for having been so banished and for having to live with "all the bad breeds, trolls and elves and monsters" (3) that were born to Cain and his descendants because of that banishment.

The relationship to Cain also suggests...

He is called a "creature of evil, grim and fierce... savage and cruel" (3). Grendel is also described as "the enemy of mankind" (4), which further explains why he bridles at hearing any happiness from human beings and why he seeks to stamp out that happiness through violence and murder. The human beings in Heorot are part of a huge family, while Grendel is described as the "walker-alone" (4). For Beowulf, such an enemy is an opportunity to achieve fame and to do so by defending humankind from something perceived as pure evil. Beowulf thus becomes the protector of home and hearth against the ravages of a creature without God. Beowulf in fact becomes God's messenger in the Christianized version of the poem, fulfilling the call Hrothgar makes ("God may easily put an end to the wild ravager's deeds!" [9]). The kind of celebrating that so angers Grendel is what makes the humans human, for they revel in their achievements and in being part of something greater than themselves, namely the army of Hrothgar and the community represented by Heorot. Their celebration at the coming of Beowulf also attracts "the walker in darkness," who arrives "wearing God's anger" (13).
The motivation for Grendel's mother is even clearer, for she seeks revenge for the death of her offspring. She is also one of those sent to dwell in darkness because of Cain's sin and is also resentful at this punishment and at the fact that human beings continue to enjoy living in the world, but she has the added reason of vengeance for the death of Grendel. She is described as "woman, monster-wife" and…