Mecha Sonic Saga
The Koopa Bros. later return in a heavily defended Bowser's Castle, where they help repel the heroes, where the group is pitted up against Kirby and Luigi in the Boss Rush of Bowser's Trials.
The Koopa Bros. later appear in the Fawful Saga, where they are brainwashed and Fawfulized by Fawful, becoming the Fawful Bros., they are freed from his control later.
While not appearing themselves, holographic copies of them are created by the Holo-Defense API to defend its Research Facility.
All four of the Bros., being Koopas, can retract into their shells, which they can use to ram into foes. The group have a signature move that involves them stacking on top of each other, with Yellow at the bottom and Red at the top, which forms a tower which they use to slam into their opponents, they also have the ability to charge up this attack, making it twice as deadly, Mecha Sonic is currently the only character to have ploughed through this attack unscathed.
- The Koopa Bros. were based on the Teenage Mutant Ninja Turtles, much how the Axem Rangers were based on the Ginyu Force and Power Rangers.