How did king Kia die?

Answer 1

He dies in the cell saga, when gohan becomes super sayin 2 and absolutely kicks cells ass a punch to the stomach made him spit out android 18, resulting in he turning back to his previous form. In his desperation he intends to blow him self up, he's about to and goku heroically says goodbye to his friends and uses instant transition to teleport cell and himself out of earth, and since king kais planet is the only one he could think of at the moment he took cell there and thus resulting in king kais death.