From the Harry Potter series and the epic poem Beowulf, how to the title characters show heroism through selflessness?
Both Harry Potter and Beowulf show heroism through selflessness specifically at the end of their respective stories. Harry takes a long time to accept his role as a hero and the only person who can defeat evil, while Beowulf explicitly acts heroic for his own purposes at first, only becoming truly selfless at the end.
Harry's journey takes several books, and many times he fights against the destiny that other wizards and prophecy have created for him. He wants to live a normal life but continuously becomes involved in important matters and adventures; he also gets himself into trouble by refusing to follow rules. His acts eventually prove to have consequences; people die because he doesn't listen to authority, and it takes him until the fourth book to fully understand this. By the end of the series, Harry is willing to sacrifice his own life to prevent others from dying, although at that point events are moving beyond his control.
Beowulf, by contrast, acts heroically throughout the poem, but initially it is entirely for his own benefit. He leads others into battle against Grendel more to gain fame and glory, but then risks his life alone to kill Grendel's mother. Later, as a benevolent king, he insists on facing a dragon alone; his selflessness is echoed by Wiglaf, who helps kill the dragon despite Beowulf's own death.
Both show the growth of character from selfish youth to learned selflessness.