The Koopalings, also known as the Koopa Kids in the Super Mario Bros. cartoons, are elite members of the Koopa Troop and the secondary antagonistic faction of the Super Mario Bros. franchise.
The term "Koopaling" is generally used to refer to the original seven Koopalings. They were originally King Bowser's children and heirs to the throne of the Koopa Kingdom but in a 2012 interview, Shigeru Miyamoto said "Our current story is the seven Koopalings are not Bowser's children."
Super Mario Bros. Series
The Koopalings appear as bosses in every game to kidnap Princess Peach and destroy the Mario Bros. while accomplishing their tasks for Bowser, but they all have been defeated in order from every world incompetently. They first appeared in Super Mario Bros. 3.
Mario & Luigi Series
After many absences, the Koopalings return as bosses in this series to stop the Mario Bros. from foiling Bower's plans. They also appeared as allies in some story modes to help the protagonists (Bowser Jr. and Captain Goomba) to defeat the villains (Fawful and Best Fitness Friends).
Paper Mario: Color Splash
The Koopalings debuted in this game as bosses. They spread around the world to guard the paint stars and stop Paper Mario from obtaining them, but they all get defeated in order. Roy is the only last Koopaling who does not have a paint star, but lure Paper Mario into a trap in Bowser's Castle. They were last seen carrying Paper Bowser on an airship, and they crash-landed (though it was seen off-screen).
According to Larry Koopa's Trophy in SSB4, he is the leader of the Koopalings. A position that some previously believed to belong to Ludwig von Koopa.
However, in Mario & Luigi: Paper Jam, the Koopalings do not seem to know who the leader among them is, with Iggy and Ludwig stating that they thought the group worked as a collective trust or even a republic.
In the DIC cartoons, the Koopalings were given different names.
Larry was Cheatsy, Roy was Bully, Wendy was Kootie Pie, Morton Jr. was Big Mouth, Ludwig was Kooky, and Lemmy and Iggy were Hip and Hop, respectively.
For whatever reason in Mario and Luigi: Superstar Saga, the Koopalings worked for Cackletta, despite her possessing Bowser. It is not known if they realized it or not.
However, in Bowser’s Minions, which takes place at the same exact time as the game, Cackletta’s minion Fawful is shown brainwashing them, so they probably didn’t notice anything.