While she is also monstrous and outcast, Grendel's mother is nonetheless also a sympathetic and emotional creature to a much greater extent than her son. The dragon that attacks Beowulf contrasts with Grendel's mother, in that his motivation is purely material. A further contrast is that the dragon's revenge attack is levelled at opponents that are disproportionate to his extreme power. Grendel's mother in turn was a single, female creature against fourteen strong, young warriors.

Beowulf could be seen as parallel to Grendel in terms of complexity of motivation. In terms of revenge, his motives are at least as complex as those of the monster. Generally the reasons for Beowulf's battles relate to the protection of his and others' values or lives. The battle against Grendel for example could not truly be termed revenge, as Beowulf's motivation relates to the living rather than the dead.

3. Hrothgar's sermon is centrally important to the events of the poem for its focus on the main character. It helps the audience form a more complete picture of Beowulf not only as mighty warrior, but also as fallible human being (Bramante). The first important point the king makes is that a warrior king should possess not only great physical strength, but also mental strength and wisdom. Secondly, the king emphasizes the fact that Beowulf is human and as such will age and die. When fighting the dragon, Beowulf accepts this and dies as he has lived: heroically.

4. Wealtheow and Hygd signify Beowulf's departure from and return to home. In Hrothgar's hall, Wealtheow is used...

As the stranger, Beowulf receives the cup last. When he returns triumphant, Beowulf is recognized by receiving the cup right after the king. Hygd plays the same role when Beowulf returns home. It is significant that no particular order is identified for receiving the cup, as Beowulf and his status are both known and recognized in his own land (Porter). When the king dies, Hygd plays the secondary role as authority figure in order to appoint a male replacement for the deceased. In this capacity, she offers Hygelac's kingdom to Beowulf. Grendel's mother, as seen above, is mainly the personification of emotional revenge. She stands in contrast with the other two women, as an outcast from civilized society. As such, Beowulf's mother is portrayed in unpleasant and unfeminine imagery (Porter). She is truly a monster. She also provides the element of surprise and challenge in the plot. Beowulf and his men do not expect her attack, and the warriors are forced to rely on the best of their skills and abilities.
Sources

Bramante, Richard D. Jr. "The Significance of Hrothgar's Sermon in Beowulf." 1988. http://bramante.metabarn.com/HrothgarsSermon.html

Porter, Dorothy Carr. "The Social Centrality of Women in Beowulf: A New Context." In The Heroic Age, Iss. 5. Summer/Autumn 2001. http://www.mun.ca/mst/heroicage/issues/5/porter1.html

Tierney-Hynes, Rebecca A. "The Heroic Ethos: Reality and Representation." 2000. http://www.chass.utoronto.ca/~cpercy/courses/1001TierneyHynes.htm