Beowulf and Achilles are excellent examples of the hero archetype. Both men exemplify traditional masculine virtues such as physical strength, courage and martial prowess, and both exhibit leadership and command respect among their peers. They are, in a word, superhuman. Nevertheless both characters possess flaws and weaknesses that make them incontestably human, and which lead to their eventual deaths.
The primary focal point for each character is their embodiment of a wide range of enviable masculine powers. Beowulf is so strong, even in old age, that his strokes break his sword in half. Achilles, with the exception of his heel, is invulnerable. Beowulf, in an almost boastful maneuver that can only serve to heighten his renown, declares;
I hereby renounce sword and the shelter of the broad shield,
the heavy war-board: hand-to-hand is how it will be-
He has no good reason to reject the use of weapons, and in fact it would give him a distinct advantage over Grendel. Yet, by discarding his weapons, he appears both superhuman (what man could conquer both his fear and the monster?) and sporting; he will fight and defeat the monster on its own terms. Consider a modern analogy; the contempt for which big game trophy hunters are often held, and how would we regard a man who dared to kill a lion with his hands? Achilles, likewise, is well-known by others, and though Homer makes little direct acclaim of his abilities, he allows characters who know of Achilles to make proud or fearful references to him, such as " lion-hearted Achilles, cleaver of the ranks of men." Reputation is as important as ability for a hero.
The two men differ in their weaknesses, and the way they are manipulated. Perhaps the greatest weakness they both have in common is ego. However, where Beowulf in many ways was able to conquer his ego, Achilles did not; in fact much of the action of the Iliad is born of Achilles' childlike brooding and refusing to fight, which brings the Achaeans "countless losses", his rage souring his wisdom and heroic responsibility. Achilles also committed what amounted to a grave and practically blasphemous indecency; dragging Hector's body around the walls of Troy, whereas Beowulf, boastful as his deeds sometimes were, nevertheless did not disrespect his fallen foes. Finally, Beowulf's power is directed against three enemies, all of them inhuman monsters, whereas Achilles fights exclusively against other men, despite arguing with Agamemnon that the Trojans had done him no harm. We might state that Beowulf is the more humanistic hero, because his actions are always undertaken to protect his people, with glory for himself as an added bonus, and never an incentive for or against taking action, as with Achilles.
This is a very interesting question to consider, because both of these epic heroes have a number of similarities in the way that they are presented as being larger-than-life figures with almost supernatural strength and courage. Both are shown to prevail over any number of enemies that "normal" men are unable to face, and both are regarded rightly as heroes in this respect. However, at the same time, the two characters are not entirely blameless or presented as examples of morally good individuals.
This is clearly the case with Achilles, who is frequently mastered by his emotions of rage and anger rather than being master of them. He is presented in certain parts of the text as almost a child as he refuses to fight after his quarrel with Agammemnon and is only tempted back into battle after his dear friend, Patroclus, is killed. Then, he acts cruelly to gain revenge, desecrating the body of Hector. This is one point of comparison with Beowulf, who is not mastered by his emotions in the same way. However, a similar challenge faces them both, as both have to choose between chasing glory and a potential early death and living a long life but dying in obscurity. For Achilles, this is something that is related to a prophecy concerning his life:
Mother tells me,
the immortal goddess Thetis with her glistening feet,
that two fates bear me on to the day of death.
If I hold out here and I lay siege to Troy,
my journey home is gone, but my glory never dies.
If I voyage back to the fatherland I love,
my pride, my glory dies...
He can either choose between a glorious but short life that will make his name immortal, or a long and obscure life which will condemn him to oblivion. In the end, the allure of pride and fame is too much for him, and he returns to battle to die a glorious death. Beowulf faces a similar challenge, as Hrothgar's wise words to him after triumphing over Grendel's mother show:
O flower of warriors, beware of that trap.
Choose, dear Beowulf, the better part,
eternal rewards. Do not give way to pride.
For a brief while your strength is in bloom
but it fades quickly; and soon there will follow
illness or the sword to lay you low,
or a sudden fire or surge of water
or jabbing blade or javelin from the air
or repellent age. Your piercing eye
will dim and darken; and death will arrive,
dear warrior, to sweep you away.
Just as with Achilles, Beowulf's decision to go and fight the dragon at the end of the text is morally questionable. He is going out to have one last adventure that he knows will more than likely result in his death. This will leave his people defenceless and without a king, showing that he is shirking his responsibilities in order to chase elusive glory. Although Achilles is shown to be less overtly heroic than Beowulf in the way that he is mastered by his emotions, at the same time, arguably, both characters place their own desire for glory and fame above all else.