Astral Odyssey: Dying Ember
Luna nodded.
"As I've said before, the key for that to happen is to strengthen your soul. Basically, you died in your world because it was time for you to die. For the people in your world, everyone is born with differing soul strength. The stronger the soul, the better hold it has on the physical body. Every accident that happens to your body whittles down the hold your soul has on the body. With every transmigration, your soul will get strengthened as it gets used to settling into physical bodies and absorbing residual soul bits left behind by the original soul. Eventually, it will come to a point where I can send you back to your body without needing my help in keeping your soul in a phys