Composite Character: In the first NES game, not only serves as the new final boss, but essentially replaces Jeff (the head-swapped Lee brother boss from the arcade version) as the boss who uses all of the player's moves.
Faux Action Girl: If we are to believe the back-story given in the original game's official soundtrack and some of the console versions, she was formerly an assistant instructor in Billy and Jimmy's old dojo. Seeing how she goes down with only one punch to the gut in the opening of the original game without putting up much a fight, her qualifications for such a job are debatable. Averted by her Neo-Geo incarnation, who does have actual fighting skills.
Groin Attack: Gives Skullmageddon one after the end credits in Neon.
Badass Mustache: Abobo's in-game sprite sported a horseshoe mustache in the original game. The character illustrations for the NES version gave Abobo a clean-shaved look though, giving him an appearance similar to Kratos or Sagat.
Canon Immigrant: At first he was just a character made up for the NES version of the first game, but later appears in the arcade version of II as a stick-wielding fighter. His name was used for the Player 2 version of Chin (shortened to "Taime" due to space limit) in the arcade version of 3.
Demoted to Dragon: In the first NES game , where he's just the last guy the player fights before the final fight with Jimmy. He's completely absent in the second NES game, although he does make an appearance in the PC Engine remake.
Sudden Name Change: To "Roper" in Battletoads & Double Dragon. The manual for the Master System version also switched his name with Jeff's.
Butt Monkey: Williams is most definitely one of these in Neon: Skullmageddon threathens to dock his pay for the monitors you break in levels 3 and 4 and 2 of his quotes when he kills you are "No dogfood for Williams today!" and "Guess who's sleeping inside tonight?"
Blind and the Beast: Jawbreaker befriends the Samantha (Commissioner Briggs' blind daughter) after kidnapping her under the Shadow Master's orders in "The Sight of Freedom". When Icepick orders him to "eliminate" the girl, Jawbreaker rebels against the Shadow Warriors and rescues her.