Source: Siren Maniacs, page 44-45
Siren: The Shibito, Part 1
Shibito Brain
The Shibito that command the troops of dog, spider and flying Shibito charged with hunting humans. The hallmark of a Shibito Brain is that unlike other Shibito, their outward appearances just about retain some of their human form, but their heads have morphed into various strange things. They are amidst the upper echelons of the Shibito ranks, but there appear to be no specific rules governing which Shibito turn into brains upon performing umi-gaeri (more accurately, this cannot be understood by humans). However, amongst the Shibito, whose intellect is inferior to that of humans, Shibito Brains are the only ones who, like half-Shibito, appear to sometimes remember some faint memories from when they were human.
Since the Shibito Brains, who control the other odd creatures, are when compared to other Shibito fairly weak (although some are quite strong...), many of them will run at full speed in the other direction when a human draws near. If they are defeated, the surrounding Shibito will also be silenced.
Those turning into Shibito
Since long ago, the villagers have called the monsters that return from the sea "Shibito" (corpse people). Immortal, they attack humans, building a community amongst themselves and finally controlling the entire village.
Those who become Shibito no longer fear death. Having ended their human lives, the looks of ecstasy sometimes witnessed on their faces - is it the joy of having attained eternal life, or the belief that they have been chosen by the Land of the Gods...? Some still have faint memories of their time as a human, but this is just because they are either attached to those memories or it is instinctual. As the number of Shibito continues to increase, the humans steadily vanish. Finally the village becomes cut off from the outside world, becoming a haven of the dead.
Top three photos: From the left, Shibito Takato, Mihama, Shimura. The red water that enters in place of their blood slowly transforms their bodies.
Middle three photos: Shibito Brains, whose bodies alone are those of a human.
Bottom three photos: The Shibito function within a community.
Half-Shibito (半屍人)
The "first stage" of Shibito, into which one transforms after a certain amount (which differs from person to person) of red water enters their body and they are called by the siren. Half-Shibito possess a duller wit than humans, but their physical abilities are mostly the same. The tears of blood flowing from their eyes are a strong outward characteristic, though this is nothing more than a physiological phenomenon showing that their blood leaves their body as it is replaced by the red water. Half-Shibito build a community with other Shibito until their preparation to become one themselves is complete, and they act following the pattern of their life as a human. Those who are prepared (to become closer to god), led by the sound of the siren, perform "umi-okuri" in the red sea.
Dog Shibito (犬屍人)
One transformation of a half-Shibito that has been "sent" to the red sea (in other words, one of the "second stage" Shibito). Only human females change into this form. The way they move as if crawling and the antennae poking out of their heads are characteristic of them, and they have completely lost all intelligence, not even wielding weapons, acting only as directed by Shibito Brains. Out of the player characters, Naoko Mihama is the only one who can be observed as having mutated into a dog Shibito (day 3 / 22:13:33). They appear to have higher heath than other Shibito, move quickly across the ground, and have a strong jumping ability, able to launch themselves onto the roof of an abandoned house in a single leap. However, they lack the intelligence to open and close doors.
About the Shibito - 1
Shibito are beings that have become immortal and transformed into strange creatures due to the effects of the red water, their bodies and minds no longer human. Here, we will explain some keywords so that you can learn more about the Shibito.
"Red water"
The red water is actually an incessant outpouring of the blood of the god (Datatsushi). Those who have red water enter their body begin to transform in order to become immortal. The reason Kyoya and Yoriko survive despite being shot in the chest is because enough red water to replace their lost blood has already entered their bodies, but that amount alone is enough to bring them closer to the residents of the "other side" (the dimension in which the god lives), and they are losing their humanity. The red water is an offering of god.
"Visions"
An ability that lets you purposely steal other people's sight and hearing, and is used by the Shibito to maintain contact with their comrades. There are even some people with "sharp senses" amongst humans who possess this ability, but direct descendants of the Kajiro family and the Shibito can select the person they want to see just by concentrating. The player characters in the game can also utilise this ability since they have taken in red water, but this is nothing more than a sign that they are becoming Shibito.
"Umi-okuri"
Umi-okuri (archive No.031) is a version of a local legend with a different nuance, which can be thought of as a rite of passage undertaken by Shibito in order to become an eternally unchanging, immortal utopia, becoming one with the red sea. With the sounding of the siren every six hours, the Shibito who have prepared for transformation into the next stage are sent into the sea, but those who have not yet made preparations to welcome the god are sent back in umi-gaeri. The period of time and number of times performed differs from person to person.
"Umi-gaeri"
To the Shibito, those who have performed "umi-gaeri" - those who have progressed further in their transformation into Shibito - can be thought of as "those who have received the blessing of the god of the Underworld and been cleansed of the sins of the human world, becoming closer to the Underworld (utopia)". Shibito are a species that live by an entirely different set of values to humans, and umi-gaeri is a sacred act to them. However, those who possess the Kajiro blood will, due to its curse, never be granted the blessing of god (unable to become Shibito).