Grendel’s mother is much older than her son, and over the centuries she has lost her ability to use language. Like Grendel, Grendel’s mother was likely born with the innate ability to speak and think in the same language as humans, but a life of isolation and animalistic living has given Grendel’s mother no reason to use language, and eventually, her ability to communicate through words died. Her inability to speak only furthers Grendel’s loneliness, as he can only communicate with his mother through vague sounds and gestures. At first, Grendel recognizes his mother as his only companion—the only other creature who actually sees him—and a being that is deeply connected to him. However, as Grendel grows into his individuality, he becomes increasingly resentful of his mother. Grendel is incredibly intelligent, and the more cerebral and intellectual his inner life becomes, the more frustrating, boring, and painful his interactions with his mother become.

However, despite her beast-like behavior, Grendel’s mother is perhaps the only source of genuine care that Grendel receives throughout his entire life. While she cannot meaningfully communicate with her son, she does have a motherly instinct toward him, rescuing him from harmful situations and even attempting to warn him when she senses impending danger. Grendel’s mother seems to know about Beowulf’s future approach before it happens and tries to tell Grendel to beware, even managing to speak in sounds reminiscent of words. However, her linguistic abilities are too far gone, and Grendel doesn’t understand what she’s saying until after Beowulf’s fateful arrival.

Both Grendel and Grendel’s mother lead a tragic and cursed life. Their linguistic and intellectual separation from each other causes them to live lonely existences even though they share a home and a mother-son bond. Grendel’s mother’s character also serves to further expose how she and her son have been unfairly ostracized from civilization. Though she is just as preternaturally powerful as her son, Grendel’s mother seems relatively uninterested in harming other creatures aside from hunting for food. Although Grendel’s mother does not die in Grendel, the ending of the novel foreshadows the fate that awaits her in the epic poem Beowulf. After Grendel’s defeat at the hands of Beowulf, the Geat warrior will also slaughter Grendel’s mother, knowing her to be just as dangerous a beast as her son. Yet, in Grendel, Grendel’s mother does little to make herself deserving of such a death. While she is a tertiary character, Gardner uses her to question whether the monsters featured in human mythology are actually deserving of the villainous status imposed upon them.