Complete Monster: Richard the Lionheart, of all people, is depicted as this. He lies, cheats, and seems to genuinely enjoy the carnage of the Crusades. He opts to slaughter the population of a city rather than accept the enormous ransom he originally demanded.
Critical Research Failure: A downplayed example with the Norwegian Harald joining the cast in the second film. Despite the setting being the mid-12th century, Harald speaks a modern Norwegian 'bokmål' dialect, when realistically he should have spoken a much older dialect such as 'nynorsk'.