Jimmy Lee

Jimmy Lee is one of the two protagonists and heroes of the Double Dragon franchise, along with his brother Jimmy Lee. However, he have been portrayed in an antagonistic role in a few appearances.

Double Dragon (NES)
In the NES port of the original Double Dragon, Jimmy appears as the final boss of the game right after Willy Mackey, instead of being a playable character like in the original version. As such, his role here is changed as the true boss of the Black Warriors and the mastermind behind Marian's kidnapping.

This change was due to technical limitations, as the developers could not implement a two-player cooperative mode like in the Arcade version, and they wanted to reenact the final battle of the original version, where the two brothers fight each other over Marian's affection. All subsequent releases ignore this game's plot, and Billy is back to his heroic self.

Double Dragon (cartoon)
In the cartoon adaptation of the series, Billy is initially introduced as one of the main villains, working under the Shadow Master under the persona of Shadow Boss. He had been kidnapped by the Shadow Master as a baby and raised by him, being taught on the way of the Black Flame. The Shadow Master eventually betrays him, after which Jimmy reunites with his brother and joins him.