Answer:
He was happy.
Explanation:
Grendel is a showy creature that does a lot of damage to a city in Denmark. Because of all his evil Beowulf, together with other warriors he pledges to defeat Grendel and free Denmark from its yoke.
However, Grendel used to be invincible, defeat warriors and devour them very easily and for that reason, when he found the hall full of warriors he was happy because he was sure that he would finish them all.
