Hrym is the leader of the giants. He is the first enemy to present himself, but will not be the last.
Voluspa - Norse Mythology Book - Verse 50
“From the east comes Hrym | with shield held high;
In giant-wrath | does the serpent writhe;
O’er the waves he twists, | and the tawny eagle
Gnaws corpses screaming; | Naglfar is loose.”