Hisako Yao (八尾比沙子) is the main antagonist in Forbidden Siren.
Previous to 1976
Hisako was originally a villager of Hanuda in 684 AD. She was the one who discovered Datatsushi's corpse during the great famine of the time. Along with two unnamed villagers, she initiates the devouring of the alien's corpse.
From this, Datatsushi emanates an intense scream (what would be known as the Siren). Hisako appeared visibly shaken by the experience while the others merely covered their ears. Subsequently, she was cursed with immortality unless Datatsushi is summoned back to life.
During the next hundred years she lost her memory, her descendants (The Kajiro family) became the most important family in the village and she will found the Mana Religion.
Probably during the early 1500's Hanuda's cult was influenced by western religions and began to imitate the Holy Communion using the flesh of a strange being; becomic increasingly esoteric. Later during the first years of the Tokugawa shogunate, the religious prosecution caused the cult to become secret; is at this time that the Homuranagi was created, in order to protect the cult from the shogunate.
After the Meiji restoration, in 1873 with the religious freedom the cult was revived under the guise of the forbidden religion; and around 1900 European missionaries are taken in by the village and find a half fish half person mummy with a strange head.
|The "Baby on the Chopping Board" legend mentions the taboo of eating something that should never be eaten, symbolising something quite characteristic. The "half human half fish" mummy impaled on the plank clearly reflects the memories of Datatsushi, being eaten alive, on a piece of wood that used to be a Mana cross. However, what the idol is actually doing at the bottom of the well is never really explained in-game. Perhaps due to the "original sin" of eating the flesh of the god (Datatsushi) long, long ago, which will never be forgotten, someone left the idol there.|
During the incident of 1976
During the 1970's she passed as the maid of the Kajiro family (her descendants) called Sumiko. She helped the Miyako Kajiro of 1976 escape with her lover Takafumi Shimura (Akira Shimura's son); she confined both in the Miyata clinic along with the Uryen.
The ritual failed and a part of the village (The Gojaku peak, Miyata's clinic, the Tabori settlement, Arato, Harayadori and Hirunotsuka) was sent into another dimension. The priest in charge of the ceremony, Reiji Makino commited suicide and a newborn (Kei Makino) was taken in order to fulfill that role in the future, they waited until both the new priest and Miyako Kajiro were ready to conduct the ritual once again.
During the incident of 2003
In 2003, at the beginning of the game, Hisako partakes a sacrificial ritual that was meant to summon Datatsushi. Kyoya Suda's sudden appearance interrupts the ritual and the Siren causes the dead villagers to rise as Shibito.
She encounters Kyoya Suda in Arato and helps him. Together, they head to the Irazu Valley Church near Karuwari. In Irazu Valley Church, at 7:00 they arrive, but Kyoya goes out shortly after in order to help someone who screamed.
There she looked at the list of the church members; as she does so her mind becomes foggy. Tomoko Maeda's parents go to the church looking for her, then she leaves the church in search for Tomoko, eventually finding her.
By 0:00, on the way to the church, she began feeling strange as if someone called her, and ordered Tomoko to enter an abandoned house filled with Shibito; then she vanished alone, switching between multiple personalities, acting as though confused, wandering about, over and over.
At 6:00, self descends in the Utsubobune, picking up the holy vessel that washes up on the shore containing Datatsushi's head, from this point onward, Hisako gains insight into her true purpose. Then by 10:00, with the help of Jun Kajiro, Hisako kidnaps Miyako and starts building a nest around the mirror pool (the source of the red water) to receive her god. The ritual is conducted successfully, summoning a premature form of Datatsushi.
But Shiro Miyata destroys the dam and the river floods the nest; the light from the sun causes Datatsushi to burn and die again, then Hisako entered Datatsushi's dimension in order to revive him once again, along with Jun Kajiro who by now was a shibito.
Kyoya fights Datatsushi and eventually decapitates it, causing her immortality and youthful appearance to be reversed. She picks up Datatsushi's head and ages rapidly before falling into a dimensional vortex, traveling through time. She gives her younger self the alien god's head, resulting in Datasushi's return.
As Hisako the Guiding Nun, as Sumiko, the maid of the previous generation Miyako, she is originally a stoutly devoted woman full of affection, and her "selves" bear no ill intentions. However, the awakened Hisako, Yao Bikuni, wishes for her own resurrection as a part of Datatsushi. Her penance, having lasted more than one thousand years, seems to be drawing to an end...
Hisako was a nun of the local Mana religion. She wore a crimson robe with salmon pink accents. She also wore the traditional Mana Cross around her neck.
Initially, her hair was kept tied into a bun, but when she became aware of her true purpose, she let her hair flow freely.
- Her name, Yao Hisako (八尾 · 比沙子) is both a reference to the Yao Bikuni (八百 · 比丘尼): Changing 百 for the homophone 尾, and 丘尼 for 沙子. And to the actress that portrayed her (Risako 梨沙子).
- The (hisa) part of her name can also be the Nanori reading (how characters used for personal names are read) of the character (寿), meaning Longevity or Long life.