In the Arturian legend, Gawain is often considered to be the most valiant knight of the Round Table, succeeding Arthur, as well as wielder of Excalibur. The character of the green knight also appears in a poem, as a tempter and judge of the knights.
On the contrary, in the film, Gawain is not yet a knight, and loses himself in debauchery and easy laziness, although he is protected by King Arthur. But when a mysterious knight comes to challenge the Round Table, Gawain recklessly offers to take it up. However, his imprudence leads him to have to find the knight a year later, and give him his head.