With what aspects of nature is Grendel associated with in Beowulf.

When one looks at Grendel as opposed to the dynamic
relationship to Beowulf one must first look at Beowulf's personality.  He is an epic
hero which means that he likes a challenge.  Grendel serves as that challenge.  Beowulf
travels to Grendel to take on the challenge.

Grendel
himself is not born of man but of a sea creature.  He is powerful and dwells in a cave. 
He seems to have no fear of man which he evidences by attacking willingly at various
times of day or night.  Grendel is like a plague that is able to wipe out large groups
of a population.  Grendal has an endurance and a penchant for violence like nature's
storms.  He lingers and terrorizes the people of
Herot.

Grendal is believed to be a decendent from the race
of Cain.