The film views anyone with power as corrupt by nature. Hrothgar himself (played by a miscast Anthony Hopkins) is an aged and bloated version of Beowulf — vain, loud, boastful. When Hrothgar commits suicide, Beowulf wins his kingdom and his queen Wealthow (Robin Wright Penn) — although she had virtually no role in the poem she is a major character in the film — she becomes Beowulf's wife, whom he betrays by taking at least one lover. In the poem, Hrothgar lives on while Beowulf returns home to the Geats and later becomes their king. We know nothing about Beowulf's wife and less about his exploits with other women.

In the poem, Beowulf is a great and flawless hero, and for this reason he is a major point in the argument for the poem's Christian sub-text. Beowulf is a Christ-like hero, and his battle against evil — embodied in the two monsters as well as the dragon — is a Christian battle of good against evil. In the film the battle that Beowulf undertakes is a battle against his own duplicity, the sins he has committed, the deceptions he has carried out. The film uses this quest for redemption to weave the two largely unrelated parts of the poem (the battles against Grendel and his mother and the battle against the dragon) into a more seamless but ultimately less satisfying narrative.

The flawed heroism of Beowulf is a specifically modern heroism. Its basis lies in the Aristotelian concept of the flawed tragic hero and even more in modern skepticism about heroes — no individual can be wholly good and unblemished, every hero must be flawed in some way. In making the story one of Beowulf's quest to redeem himself from the sins and errors of his life, the film fundamentally reconceives the story in the poem. In the poem, when the dragon begins its rampage Beowulf acts out of heroic goodness to confront evil and protect a suffering people. He does this even though he recognizes that his death may result. The poem's concern is with heroism and the character of a hero, not with tragedy. In the film he seeks personal redemption and expiation of his own sins of deceit and lust. His motive is selfish, not altruistic.

The film also gives us an Oedipal story. Grendel's mother is an evil demon who can take on the form of a beautiful sexual temptress. She seduces Hrothgar, and from this union comes Grendel. Later she seduces Beowulf, and from this union comes the dragon. Both sons seek to slay their fathers, partially from jealousy and partially out of revenge against the fathers whose duplicity and corruption are at the root of their progeny's being. This is a twist to the story largely absent from the poem.