>>58424721as seen in the animation for her alter outfit, nothing happens to the Kiara of that universe until she interacts with them in which case they die and are swapped out into the other Kiara's universe
this means that potentially a universe becomes Kiara-less for a time if she reincarnates out of that universe until the two Kiaras meet and one is swapped back in (there are probably universes that just have no Kiara in them after she reincarnated)
although it should be noted, as seen by her re-debut streams, Kiara can willingly reincarnate back into the same universe each time and stay there, she doesn't have to go into another one if she doesn't want to
