|Japanese name||四方月 宗也 （よもつき そうや）|
|Romaji name||Yomotsuki Souya|
|Cause of death||Killed by Sakuya|
|Encountered in||Shrine of the Conscious Mind (Chapter 11)
Tsukuyomi Lighthouse (Final Chapter)
|Family||Member of the Yomotsuki Family, Ruka Minazuki(daughter), Sayaka Minazuki(former wife)|
|Appearances||Fatal Frame IV: Mask of the Lunar Eclipse|
|Voice actor (Jp)||Takahiro Sakurai|
|Voice actor (Eng)||None|
Souya Yomotsuki is a hostile male spirit in Fatal Frame IV: Mask of the Lunar Eclipse. He had a task to make the masks that the Utsuwa and Kanade used in the Kagura Ritual. It is discovered through gameplay that Souya is, in fact, Ruka's father. He is also a descendant of Souetsu Yomotsuki.
Souya, being a member of the Yomotsuki Family, was handed down the craft of mask-making that had been in the family for generations, specifically making the masks for both the ancient Kiraigou and the more modern Rougetsu Kagura. Then, in 1970, Shigeto Haibara, director of Haibara Hospital and a prominent figure on the island, called on Souya to help him revive the Kiraigou. This version of the ritual had been stopped generations before, in Souetsu's era, after the mask the dancer was using broke and caused the ritual to fail. This caused the woman to Bloom and kill a number of the islanders, in a disaster known as the Day Without Suffering; out of fear, the islanders demanded that the ritual be stopped, and even mentioning its name became taboo on the island.
Souya, certain that by studying diligently and working hard he could create the "true" mask that would not fail, set about making a new, better mask to use in the ritual. Souya also made masks for the Kanade to be used in the ritual, even including one for his own daughter. He spent all of his time confined in his workshop, and was secretive about what he was doing. All of this worried his wife, Sayaka, and Ruka would repeatedly ask why her father didn't come to visit any more. Eventually the mask was finished and Souya passed it on to Shigeto, saying that he would be praying for the Kiraigou's success.
The ritual, however, ended in failure, the mask once again breaking. Sakuya, the dancer, was left in a coma-like state between life and death, imprisoned in Rougetsu Hall's basement. After Ruka was retrieved from the hospital basement by a detective on the island, Sayaka took her away from the island, away from the Haibaras and Souya. Knowing that the disaster of Souetsu's time was certain to happen again, and blaming himself for the impending destruction, Souya would sit all alone in the Meditation Cave below the island, saying that all he wanted until his certain death was "peace and quiet".
In 1972, two years after the failed Kiraigou, Sakuya Haibara broke out of her confinement cell in the basement of Rougetsu Hall and began to make her way across the island, spreading Blooming amongst the islanders. Sakuya encountered Souya in the cave in which he spent all of his time and presumably spread the curse to him, too, although it is never shown (the flashback cuts out as she walks up to him).
Souya initially appears as a vanishing ghost, and later becomes an attacking ghost in chapters 11 and 12. He then appears in the game's ending, picking up Sakuya's discarded mask and smiling at Ruka before crossing over to the Other Side through the newly-opened portal in the sea.
- Souya has two attacks. One involves him sending the mask he carries to chase the character (similar to the skull attack of the Veiled Priests from Fatal Frame II); this attack cannot be avoided unless it is cancelled by a Zero Shot before the mask is released. In the other, he flies toward the character and attempts to push the mask onto their face.
- Souya is in possession of one of the pieces of the fragmented ritual mask - defeating him for a final time in the Lighthouse leads him to drop the Forehead piece, thus completing the mask.