Monsters; Some Good, Some Evil
The Ballad of Grendel's Mother and Beowulf
Beowulf goes into the fight with his sword, but the sword doesn’t work against Grendel’s mother. Beowulf has to find another way to kill her, and then he finds a giant-made sword and uses that to kill Grendel’s mother. The theme is that battles don’t always seem as easy as they do, sometimes the hero have to find other ways to win.