I have heard it said by my people in hall,
Counselors who live in the upland country,
That they have seen two such creatures
Prowling the moors, huge marauders
From some other world. One of these things,
As far as anyone ever can discern,
Looks like a woman; the other, warped
In the shape of a man, moves beyond the pale
Bigger than any man, an unnatural birth
Called Grendel by country people
In former days. They are fatherless creatures,
And their whole ancestry is hidden in a past
Of demons and ghosts.

Beowulf, Seamus Heaney (trans.)

Lines 1345-1357: Hrothgar is speaking about the demon Grendel and his mother, who are descendants of Cain.