Question

"'Neath the cloudy cliffs came from the moor then
Grendel going, God's anger bare he.
The monster intended some one of earthmen
In the hall-building grand to entrap and make way with" how does this poem helps show that Grendel is a monster

Answer 1

While I can't tell much from the first line due to a lack of context, I can tell you that a moor is like a swamp-like hilly biome, and is not the nicest of places to live. The last two lines also give a sense of sinister intent, as Grendel seems to desire trapping the people in his home. While evil humans can also do that, in the era of Beowulf, such things aren't common in humans.