The Anglo-Saxons believed in many different creatures and monsters. They populated their world and haunted their nightmares. Grendel is one of three foes, along with Grendel's mother and a dragon, in the Anglo-Saxon epic poem Beowulf. Grendel is thought of as a huge troll-like creature who dwells in a swamp or a cave. Those are the sorts of locations the Saxons thought trolls lived. Beowulf eventually kills Grendel.

There were just a few creatures who the Anglo-Saxons believed inhabited the woods and hills. It was for fear of them that they avoided such places in the night. When bad things happened they would blame them and they would pray to Woden and Freya to protect their families.