The Tattooed Priestess (刺青ノ巫女 Shisei no Miko) is a woman who is chosen or by her own will to perform the Piercing of Soul ritual, which involves two Engravers tattoo the Priestess with the Ink of the Soul, which is made from the blood of the living and the dead, and the Impalement Ritual, which involves four Handmaidens impaling the Priestess in the hands and feet. The Priestess has to be asleep in order to absorb the pain from others who visit the shrine. If the Priestess wakes up and performs the Rite of Stakes, the Rift will open and suffering will be unleashed on all.
The Chosen Ones
Young maidens who were acquainted the pain of losing a loved one were brought to the Kuze Shrine. They mustn't have any living relatives in order to be chosen as Priestesses.
Once a maiden is chosen and adopted by the Kuze family, she concentrates all her emotions, pain, grief, sorrow and love in a mirror which is called 'The Mirror Of Loss'. Once the mirror contains all her emotions, the Priestess must shatter it. The purpose of this action is to severe all the maiden's ties with the mortal soil, in order to gain the purifying power required for the rituals.
The Engravers tattoo the Priestess with the Snake & Holly Tattoo pattern to symbolize the pain of loss. The Engravers pierce their own arms with the tattoo needles and gather Ink of the Soul from both corpses and living worshipers.
The Priestess must meditate with the Mirror of Loss in order for her to separate herself from her emotions and earthly ties. She forsakes her emotions and becomes completely cleansed via shattering the Mirror at the end of the Rite.
The four Handmaidens, impale the Priestess's hands and feet with stone stakes so that she does not wander during her sleep. While they impale the Priestess in the Chamber of Thorns, the four pacifiers sing the Handmaiden's Song to calm the Priestess and they pray for her to dream eternally.
If the Priestess proves to be unworthy by failing in the following ways: succumbing to the pain, remorse, being unable to sleep peacefully. The Priestess is stripped of her sacred tattoos by being skinned. The body is sent to the Other Side in a boat while her skin is enshrined in the Tattoo Altar. The handmaidens sing their lullaby to the enshrined skin so that the pain of the tattoo may not leave the skin.