The Koopalings (occasionally called Koopa Kids in the cartoons, not to be confused with the actual Koopa Kids) are the eldest seven of King Bowser Koopa's eight children. This makes all of them the heirs of the Koopa Kingdom. Oftentimes, the Koopalings act as high-ranking leaders of the Koopa Troop and mostly appear as bosses in the variousMario series games. The Koopalings are known for taking long hiatus between their appearances, but all most recently appear in New Super Mario Bros. Wii.
Bowser also has an eighth child, Bowser Jr., who was introduced many years after the Koopalings made their debut. Bowser Jr.'s status as a Koopaling has not yet been completely clarified, as he has yet to be officially referred to as one, but associates himself with his siblings in New Super Mario Bros. Wii. The official Prima Guide of said game refers to Bowser Jr. on one page as a "bothersome Koopaling." Other materials such as the Japanese version makes it clear, however, that the seven Koopalings are all one rank below Junior.
In the Mugen Ultimate All-Star Z Series, The Koopalings first appeared in Episode 3 after Captain Ginyu goes to Bowser's Castle to Get Bowser to Help him Destroy the Entire City as The Koopalings waited forever for their Father to Arrive who was Killed By Goku, Kammy was the only one who Could Take Care of the Koopalings Until Gogeta used a Destructive Bomb to Try and Kill Akuma but It Failed. After The Gouki Masters Event Ended the Koopalings were in Heaven until a Dancing Banana appears and Sends all of Them To Hell. Then They were Encountered by Their Father and Were forced to Train Harder Until They're Ready to Take Out The Heroes.