Grendel's mother embodies the theme of revenge as she buries her grief in an assault on Heorot. Again the Beowulf poet reminds us that she is a descendant of Cain; but there is something very human about her motivation, which John Gardner explores compassionately in his novel Grendel (1971). Although she is smaller and weaker than her son and lacks his magical protection from weapons, she is determined to avenge his death and retrieve the gruesome trophy that hangs under Heorot's roof. Once in the hall, she faces a number of warriors who, in force, probably can defeat her. She grabs one, Aeschere, Hrothgar's "dearest warrior" (1296) and chief adviser. Carrying the man as well as her son's arm, she retreats to the mere.
Beowulf is once more challenged by the possibility of increased reward — treasure and fame — and is further motivated by his devotion to Hrothgar. In his pre-dawn meeting with the king, Beowulf is informed of a rumor that has, for years, suggested the existence of two ogres, one possibly in the shape of a woman. Their den reportedly is hidden in a dark mere deep within "high wolf-country" (1357), a secret place amid wind-swept cliffs and "frost-bound trees" (1364).
The poet's description of the mere and its surroundings is especially eerie and effective. The imagery is specific, powerful, and dark. We are told that not even the wisest of humans knows what is at the bottom of the lake. The lake is so forbidding that a hart, chased by savage hounds, will die facing the dogs rather than seek safety by plunging into the water. "Not a pleasant place!" says the poet in classic understatement (an example of litotes). In fact, this place is very evil. The mere is "overhung with roots that sag and clutch" (1363); it seems to burst into flame at night, portending evil and reminding the audience of the ugly light that "shone out like fire" (727) from Grendel's eyes. In contrast to the joyful light of Heorot, here the hills are dark; black waves erupt from the mere; a "gloomy wind / stirs awful storms till the air turns choking, / the heavens weep" (1374–76).
