Double Dragon (ダブルドラゴン?) is a beat 'em up video game series initially developed by Technōs Japan, who also developed the Kunio-kun series (Renegade, Super Dodge Ball and River City Ransom). The series stars twin brothers, Billy and Jimmy Lee, who are followers of a fictional martial art called Sōsetsuken (双截拳), as they fight against various adversaries and rivals. Due to the popularity of the game series, an animated series and live-action film adaptation have also been produced.