Chronicles of Soulbinding

People have three souls. After death, the Heavenly Soul returns to heaven and the Earthly Soul returns to earth. The Life Soul may wander among the tombs, but eventually it too will dissipate. The more powerful a person is, the stronger their Life Soul. It can remain between heaven and earth for a long time, even until the next reincarnation, when the Heavenly and Earthly Souls reunite with it. Such people are known as reincarnators. They are born with memories of their past lives, and their experience and abilities far surpass those of ordinary people. When the Wheel of Light completes four rotations and the seven spirits merge into one, the Life Soul can leave the body. It can withstand heavenly lightning without dispersing and remain unharmed by water and fire, transcending the Three Realms and escaping the Five Elements. But how can one make the Wheel of Light complete four rotations and the seven spirits merge into one?