Question

In what way is grendel a modern day monster rather than a traditional historical monster

Answer 1

a historical meaning of monster was a spiritual demon, such as the devil (Satan). But as the Meaning fluctuated after time the basic meaning would mean a scary creature, spiritually (demon) or physically (bigfoot).

Answer 2

Grendel is written from the perspective of the monster, while traditional monsters are illustrated as the evil that does nothing but destroys. The reader doesn't really get any insight into what it thinks. This is the case in Grendel, where all chapters are from the monsters perspectives, where the monster contemplates his actions and surroundings.