What is the central issue of Beowulf?
The central issue of the poem is about selfless heroism. The poem follows the hero Beowulf from the time he is a young man and saves a neighboring tribe from two evil monsters. The first monster named Grendel has been ravaging their country for over a decade. Beowulf kills the monster and then is forced into a battle with the monster's mother.
After he kills her too, Beowulf returns to his own country and eventually becomes king. When Beowulf is old, an evil dragon begins to ravage his own country Beowulf goes out to challenge this dragon, also. Beowulf is successful in killing the third dragon, but also loses his own life. Thus, he becomes an archetype for an epic hero.
I tend to believe there are several central issues, among them heroism, absolutely. However, there are also other issues present. One of them is self-sacrifice and its cost. Beowulf chose the life of a hero, which meant he would have to live a life of constant danger and with the knowledge that he could be killed at any time when he chose to defend others, etc. He chose to sacrifice many normalcies of life in order to be a hero. Being a hero came with man costs. In the end, he sacrifices himself (even when he is old) to defend his kingdom and loses his life in the process.