The final and 5th of the Major Mysteries is the self-creation of the causal body, associated with willpower. Through the first 4 initiations, kundalini is raised in the physical body, vital body, astral body, and mental body, making the Innermost self a Buddha. With the 5th serpent of fire, the will of the Human Soul (Tiphereth) must reflect the will of the Father, so that the will of Christ can finally emerge.
As the kundalini rises through each vertebra in the spinal column, the initiate must pass the tests symbolized in the first 33 arcana of the Tarot. When completed, the human's will becomes Christ's will. Then one is prepared for the incarnation of Christ and enters the path of the bodhisattva, where one can perform great sacrifices for suffering humanity.