Yeah but the chaos gods show up at the unwinding of a brettonian civil war being won by a nasty dude who claims to be unbeatable. In his arrogance, he roams the lands offering the realm to any knight who can defeat him in a duel.

He spends a while mowing down challengers, revealing an unholy, unnatural strength he gained by basically selling his soul in exchange for the strength to beat "any mortal man". Just when it seems there's nobody left, the green knight appears and says "yo, u still doin that thing with the duels?"

He realized he fucked up and tries to run away but gets his head on a stick. The Lady is like "my man" and brings him back to life, returning brettonia's true king and consequently getting rid of the green knight, which is a lousy mechanic and in late game has a hard time staying relevant with heroes who have skill trees to level up