"Beowulf" and "Sir Gawain and the Green Knight", are both complex in thematic content and structure. They're both subject to various interpretations, symbolically and thematically. Moreover, there are several recurring instances of a similar theme that can be found throughout the quests and characters in both stories: heroism.
"Beowulf" is the story of a hero who is, "A protector of his people, pledged to uphold truth, justice, and to respect tradition" (Beowulf). This quote defines Beowulf as the type of hero that society wants him to be. Beowulf's first conflict on his journey is to fight a beast that has been killing strong honorable soldiers for such a long time. Not only would he defeat it, but he would do it with no weapons or armor. Beowulf soon confronts Grendel as planned and using his bare hands, defeats the beast, taking his arm for a trophy. Finally ridding the great Danes king of this problem his actions impose a new problem on them. Now Grendel's mother seeks revenge. .
The fight between Grendel's' mother is an important turning point in the story, because this is when Beowulf's "super-human" strength begins to wane. We now are introduced to a force that is little by little weakening Beowulf; he is slowly aging and becoming less and less powerful. In such a suspenseful moment, something comes to the aid of our hero Beowulf. On the wall of the underwater great hall is a giant sword that carried magic and was so massive that no ordinary man could lift it. Beowulf being the "superman" that he is, easily picks the sword off its display mount strikes it down onto the neck of Grendel's mother, thus cutting her head off. Beowulf's last battle is against the most powerful medieval beast of all, a dragon. In Beowulf's previous fight he utilized some outside help, but this time even outside help isn't enough. A young soldier, Wiglaf runs to Beowulf and aids him and delivers a fatal blow to the dragon's neck that weakens the dragon enough to allow Beowulf to deliver the dragon's final death blow, a slash from head to toe, down its belly.