When Rei first enters the mansion in her dreams, she is chased by the ghost of a Tattooed Priestess, a shrine maiden of the Kuze Shrine. Rei discovers that their purpose is to be engraved by a sacred tattoo to stop the spread of The Rift, the divide between the land of the living and the land of the dead. To keep the Rift at bay, the tattoo, in the pattern of a Snake and Holly, is instilled with the pains of those who visit the shrine and offer it. This process, called the Piercing of the Soul is done with ink made from the blood of the living and the dead, called Ink of the Soul. Through this ceremony, the tattooed priestess is able to take away the sorrows and suffering of those who come to the shrine, and stop the Rift from spreading. However, because of the agonizing pain she is under, measures must be taken to ensure the priestess will be at peace. At the end of the ritual, the priestess is taken to the Chamber of Thorns deep within the shrine and impaled inside its walls. She is then sung a lullaby to ensure that she falls into a deep sleep and never wakes from her pain. Through this Impalement Ritual, the priestess is kept from wandering the shrine, and allowing the pain engraved on her to affect others.
The last Tattooed Priestess to undergo these rituals was a young woman named Reika Yukishiro. Reika came from a village beside the Kuze Shrine, where she met and fell in love with a man named Kaname Ototsuki. One day, when Kaname was away, disaster befell the village and Reika's whole family was killed. When the shrine offered to adopt Reika, she agreed, hoping that by becoming the Tattooed Priestess she would be able to ease the pain of those who have felt loss, as she has.
Miku follows her brother deep within the manor.
When the time to sleep in the Chamber of Thorns came, Reika was unable to forget Kaname, and her dreams began to affect him. Kaname visited the shrine and, with the help of a handmaiden, found Reika within the Chamber of Thorns. This was strictly against the code of the shrine, and when the Kuze Family Head found out, she rushed to the chamber and killed Kaname in front of the awake Reika. Devastated, Reika lost control of the tattoo's pain, allowing the Rift to be unleashed. In order to contain the Rift, the shrine's carpenters and handmaidens were sacrificed to seal the shrine within a dream. But the Tattooed Priestess's pain could not be controlled, and those who survived disaster and suffer grief over the dead are haunted by the Manor of Sleep and the Tattooed Curse.
Rei is lured into the manor as she continues to think of Yuu, however, those who continue to follow the dead into the manor are eventually consumed by the cursed tattoo and are forever trapped inside the dream. Miku hoped to be with her brother Mafuyu and so follows him deep into the manor. She eventually goes too far and becomes unable to wake from the dream. Rei is unable to bring her back and as things begin to seem hopeless, Yuu's friend Kei Amakura visits Rei in her home. Kei is the uncle of Mio and Mayu Amakura, and since the events of Fatal Frame II, Mio has been suffering from the Tattooed Curse and dreaming of the Manor of Sleep. Hoping to find a cure for his niece, Kei fervently researched the curse and the Kuze Shrine, but eventually, he began to enter the dream himself. Kei came to Rei to seek her insight and pay his respects to Yuu.
Kei enters the Chamber of Thorns.
Kei brings his research findings out and proposes his plan to Rei. Kei believes that to subdue the Tattooed Priestess for good, they must venture into the Chamber of Thorns and impale the priestess with the Tattooed Stakes belonging to the handmaidens. Kei searched for the stakes and after finding them, enters the chamber. Upon entering, Kei begins to feel an enormous force, as if the chamber is engulfed in darkness. Kei attempts to impale Reika with the stakes, but he discovers that Reika has been pinned down the whole time. Suddenly, Reika begins to break free from her stakes, and before Kei is able to escape, the chamber doors seal shut. The next morning, Rei sees that Kei has been taken by the curse as well. Rei is determined to end this curse, and decides that she needs to enter the Chamber of Thorns herself. When Rei arrives, Reika rises and starts to pursue Rei. With the power of the Camera Obscura, Rei is able to defeat Reika, who falls and asks to finally be let to sleep.
There is only one ending cinematic that plays after completing Fatal Frame III. However, after finishing the game at least once and fulfilling certain tasks during the next playthrough, an additional ending can be achieved where all main protagonists survive.
