Grendel is descended from Cain, the biblical figure who murdered his brother Abel. In the Old English epic poem Beowulf , Grendel is described as a member of "Cain's clan," a lineage cursed by God and condemned to be outcasts and monsters. This ancestry marks Grendel as a creature of darkness and evil, exiled from human society and doomed to wander and terrorize

. This descent from Cain explains Grendel's role as a hostile and vengeful monster in the poem, embodying both physical and moral evil. His lineage is often interpreted as a symbol of the cursed and outcast nature of his character, linking him to the first act of fratricide in the Bible and thus to a legacy of sin and exile