This question is about "Grendel" by John Gardner.
Answer and Explanation:
Grendel feels very lonely and anguished because he cannot maintain social relationships with any living being, as he is the only one of his kind. He fully wishes to find a company, someone with whom he can talk and share experiences, however, he only has contact with his mother and they are unable to communicate. Grendel, manages to understand human beings and to be touched by his creations, but humans are afraid of him and attack him causing him to retaliate violently.
This increases the suffering and loneliness of Grendel, who was cursed in addition to not being hurt and being immortal, which makes him sad to have to live like this forever. However, when he fights with Beowulf he is surprised to be hit to the death and is happy and grateful that all his loneliness will end now that he can finally die.