All individuals are one of the many incarnations that the Higher Self or the "real" you, sends to garner experiences on the third density, in this case, Earth. When an individual dies, the energy stream is withdrawn from the physical body. Without the physical constraint, an individual is allowed to spend more time exploring the third, fourth, and parts of the fifth densities in order to keep building a portfolio of life experiences. This is done until the energy stream is completely absorbed back into the Higher Self. This happens when all of the incarnations have achieved their main objectives, at which point the individual and its other incarnations are merged back with your Higher Self, the "real" you.