How does Ian Serraillier use imagery in Beowulf the Warrior?

Imagery:

"A hideous monster lurked, fiend from hell,/ Misbegotten son of a foul mother,/ Grendel his name, hating the sound of the harp,/ The minstrel's song, the bold merriment of men/ In whose distorted likeness he was shaped/ Twice six feet tall, with arms of hairy gorilla/ And red ferocious eyes and ravening jaws."

"Pouncing on the nearest/ Tore him limb from limb and swallowed him whole,/ Sucking the blood in streams, crunching the bones./ Half-gorged, his gross appetite still unslaked,/ Greedily he reached his hand for the next - little reckoning for Beowulf."