The Winter King features a central protagonist, Derfel Cadarn, in a significant same-sex relationship. This portrayal is handled with dignity and complexity, contributing to his character arc without resorting to negative stereotypes or making his identity a source of ridicule. The narrative treats the relationship respectfully, even amidst tragic external circumstances.

The series adapts Bernard Cornwell's 'Warlord Chronicles,' set in 5th-century Britain. Key characters like Merlin and Guinevere, canonically depicted as Britons (white) in the source material, are portrayed by Black actors in the 2023 adaptation.

The film frequently portrays the Christian institution and many of its leaders as politically manipulative, rigid, and hypocritical, often using faith as a tool for power rather than spiritual guidance. While individual characters may hold sincere Christian beliefs, the overarching narrative highlights the problematic aspects of the Church's influence and intolerance towards other faiths.