General Copper (or General Kappa) is an unseen (both in anime and manga) member of Red Ribbon Army. Copper commanded Captain Yellow, Colonel Violet and Colonel Silver.
It has been suggested that General Copper survived the decimation of the Red Ribbon Army Headquarters as, almost immediately before that happened, Commander Red told Staff Officier Black to give the Dragon Radar to General Copper for the General to find one of the Dragon Ball (Object) known to exist somewhere in his base's vicinity.
It is unkown what happend to Copper after this. Some think he murdered Oolong and posed as him in a pig suit for the rest of the series starting at the start of Z. This could explain Oolongs diminshing role since no one cared about Oolong no one bothered to check. (this is obviously a joke).