Humbaba (Akkadian spelling, Huwawa, Sumerian) is a monster appointed by the weather god Enlil to guard the Forest of Cedars. In Tablet I he is described by Enkidu as:
''When he roars it is like the torrent of the storm, his breath is like fire, and his jaws are death itself. He guards the cedars so well that when the wild heifer stirs in the forest, though she is sixty leagues distant, he hears her"
In Tablet II:
"Humbaba’s roar is a flood, his mouth is death and his breath is fire! He can hear a hundred leagues away any [rustling?] in his forest! Who would go down into his forest!"
Essentially, the character of Humbaba is that of an inimical force of nature, personified as a terrifying giant combining the characteristics of beast and man magnified to superhuman size.
Initially, Enkidu is restless in Uruk, and thus the quest. Gilgamesh initially is frightened, but Enkidu encourages him. Next, Humbaba offers Gilgamesh all the cedars and himself as a servant, but Enkidu (1) wants the fame and glory of killing him and (2) insists that if they do not kill him quickly before the gods arrive, the gods will intervene and prevent the death of Humbaba and destruction and looting of the sacred trees.