Beowulf Good vs. Evil Quotes
How we cite our quotes:
In the end each clan on the outlying coasts beyond the whale-road had to yield to him and began to pay tribute. That was one good king. (9-11)
So times were pleasant for the people there until finally one, a fiend out of hell, began to work his evil in the world. (99-101)
Grendel isn't just the enemy – he's a personification, or maybe that should be monster-fication, of everything that is evil. He's literally a "fiend out of hell," a descendant of Cain, inherently rotten.
"I had a fixed purpose when I put to sea. As I sat in the boat with my band of men, I meant to perform to the uttermost what your people wanted or perish in the attempt, in the fiend's clutches. And I shall fulfill that purpose, prove myself with a proud deed or meet my death here in the mead-hall." (632-638)
It's all or nothing in this fight to the death: the good warrior Beowulf against the evil demon Grendel. Things can't get much more clear cut than that.