Unlike Grendel, who was simply a bitter monster who could not participate in the festivities of the mead hall, Grendel's mother has more than one reason to kill; he simply wants to avenge his son's death. In the same way that Hrothgar and Beowulf avenged the deaths of the poor civilians that Grendel had killed, Grendel's mother tries to get due justice for her son. This is certainly not uncommon for literature of this time, and puts Grendel and Beowulf's mother on a more even playing field when it comes time to duel. Unlike his battle with Grendel, Beowulf has difficulty when fighting Grendel's mother. Although “the strongest of warriors [Beowulf] stumbled and fell” during the altercation with Grendel's mother, there is no sign of real struggle from his battle with Grendel. This justifies the poem's revenge motif; since Grendel's mother had a real reason to kill civilians, she is a stronger character and more equally matched to Beowulf, unlike Grendel who killed for Beowulf's sake.