John Gardner's Grendel is seemingly a story based on the poem Beowulf. It is easy to see that the book is meant to depict the story of Beowulf from the point of view of the hated and feared monster. While this is true, we also learn a lot about human nature from the isolated character Grendel. The character of Grendel is angry at the world and kills humans savagely to express this anger. These killings actually have little effect on the human's way of life. This proves the character of Grendel is really a representation of existentialism.
Existentialism was born from common religion. The first existentialists came to their beliefs because of an event that made them re-evaluate themselves and their ideals. As existentialism became more popular and a more recognized belief and way of life, it was done so with a feeling that religion had failed the people.
In the beginning of the story line, Grendel listens to the Shaper sing his tales and spin his web of events. The Shaper is representative of religion. Just as many religions do, the Shaper molds events and interprets them in ways to make the people happy. .
Grendel finds hope and love in the Shapers songs, and they put him at ease. As Grendel listens to the shapers stories over time, he realized that they are fabricated and used o make men feel good about themselves. This bothers him until he faces his questioning of his ideals.
The Dragon in the story is representative of the internal fight existing within Grendel. The Dragons thoughts, questions, and theories have been haunting Grendel, although he tries to ignore them. Gardner uses the dragon to illustrate the internal struggle within Grendel.
The Dragon teaches Grendel that his actions are not important. He shows Grendel that his end will always come and he will never have an impact on human life. This notion of self-worthlessness is the first and most fundamental theme in existentialism.