Sonny Lee is a playable character introduced in the arcade version of Double Dragon 3: The Rosetta Stone. He is the character to whom the third player is assigned when they choose to play as a Lee brother, essentially being a palette swap of Billy and Jimmy with orange hair and a yellow version of their outfit.
He later reappeared as an unlockable character in Double Dragon IV.
Since Sonny only existed to provide another Lee brother for the three-player mode in the arcade version of Double Dragon 3: The Rosetta Stone (due to the game allowing multiple players to control the same character type), he was not given an official backstory and his relation to Billy and Jimmy –whether he was actually a third sibling or simply a fellow Sou-Setsu-Ken practitioner– was left to ambiguity.
Because the export version forced players to start the game off as a Lee brother and acquire the other character types through in-game item shops, Sonny served as the default third player character in that version (as opposed to the Japanese version, which allowed players to start the game off as any character type). As a result, Sonny is shown prominently alongside Billy and Jimmy in the American flyer and cabinet art, which depicted him wearing black pants and a yellow tank top instead of the actual outfit he wears in the game, making him stand out next to the other Lee brothers.
Sonny returned as an unlockable character in Double Dragon IV. While he still wasn't given a background story, in the game he was specifically given the surname "Lee", implying that he most likely is Billy and Jimmy's third brother. Interestingly enough, he was also given a different moveset, which, while not necessarily make him more powerful, does raise the question on why his fighting style is different, when and where he learned it, as well as if he was estranged from his supposed siblings during their raising as martial artists.
- Sonny is featured prominently in the artwork for Tiger Electronics' Double Dragon 3 LCD video game, which is reused from the arcade game's promotional flyer. Despite this, he is never actually mentioned in the manual, which instead mentions three of the four heroes from the NES version (Billy, Chin and Ranzou).
- In a prototype version of Double Dragon II: The Revenge for the arcades, Jimmy (Player 2) wore a yellow outfit much like the one Sonny wears. This was due to Jimmy originally sharing his palette data with Marian, who wears a yellow dress in the game.
- East Technology, the developers of Double Dragon 3, would reuse the name "Sonny" for another playable character in their beat 'em up Silent Dragon.