What theme does this suggest about the struggle between good and evil?

At heart, Beowulf is an epic poem about good vs Evil. Beowulf is a masculine Viking warrior who battles the descendant of Cain (Grendel) and even a nasty evil dragon. Good and evil are polarized concepts. Good means honor, loyalty, strength, and pride where as evil means demonic creatures that are bad and are hideous to look at. The “good “ (Vikings) are guided by fate and reputation while the evil (Grendel and Mom) are just disgruntled and angry.