The lines are talking about Grendel. The first two lines are the lines where the creature is first introduced into the poem. It reveals that Grendel was jealous of something for a long time. He was jealous of the happiness of Danes in Heoret.<span />
It seems that you have missed the necessary options for us to answer this question, so I had to look for it. These lines are from Beowulf and the character that is described in these lines is GRENDEL. Hope this answers your question. Have a great day ahead!