"During the period of transition from this world to yukai, the hidden world of subtle energy, the spirit-soul is at its most vulnerable. It can be likened to a delicate butterfly, at the moment of emergence from its chrysalis. Therefore, there are spirits entrusted with the task of protecting the spirit-soul from danger at this time. In most cases, the spirits of deceased ancestors or friends of the dead come to meet and greet the dead. These spirits in turn receive instruction from higher ranks of spirit so that they may give useful guidance to their dead relatives or friends."