Frankenstein's monster fits the idea of a true hero, rather than the romantic view of heroism shared by society. He is chivalrous and loyal. Showing his chivalry by helping a family in need, he still accepts their hatred of him. He helps others although he receives nothing in return and holds absolute loyalty to his creator. Frankenstein shuns his creation and devotes his life to killing the monster. However, the same monster he hunts until death is the first to show respect to the fallen master after his death. The monster builds a funeral pyre to honour Frankenstein whose despite for him is ceaseless. His loyalty extends as far as the ritual suicide he commits while cremating the body of his creator.
Most importantly, the monster is true to himself. Society wishes that he would cease to exist, but their opinion is irrelevant to him. His creator disdains him, but the monster learns to cope with his own emotions, supporting himself. The monster relies solely on what he believes in, not in what society believes to be important. His actions are based upon his own assessments of situations, rather than what is socially acceptable.
Grendel, like Frankenstein's monster, is isolated from society, and his actions classify him as a true hero. Grendel has little outside influence and has to rely on his own emotions to make decisions. Grendel is the epitome of "blind courage". For example, when the bull attacks Grendel, he simply calculates the bull's movements and fearlessly moves out of the way. Even when the bull rips through his leg, Grendel is not afraid.