Beowulf possessed superior physical strength. If weapons were useless he'd use his hands and the strength in his fingers. (218-220) Beowulf was the strongest of the soldiers. When he was called to fight for his people, the anger for his enemy would even double his strength.
Beowulf was one of the bravest of his time. Vehemently going into battle, horror and death were only a few things he had to face just to save people in mortal danger. " I shall win the gold by my courage, or else mortal combat, doom of battle, will bear your lord away." (291-296) Beowulf always went into battle knowing he could die at any moment, but still had enough courage to confront evil with his head held high.
Nothing kept Beowulf from fighting for his people, or anyone else that needed him. He was always determined to win and care about nothing else, not even his life. " Of being worn to war, longed only for fame, leaped back into battle." (215-218) Because he wanted so bad to prove his self-worth and earn glory he would never let anyone fight his battles for him. Beowulf was resolute in everything that was put on his plate.
Being an epic hero takes someone just like Beowulf, with his superior strength, bravery beyond belief and determination that helped him succeed in everything he did.