Source: Siren 2 Maniacs, page 136-137
Siren 2: Archive 080~083
[No. 080] Ryuhei Mikami's Notebook
The notebook of Ryuhei Mikami, conducting research on Yamijima as a field archaeologist. It contains various notes, almost like a diary. This item provides clues as to what he was thinking in the summer of 1976 when Tsuneo Ohta and the others conduct a raid. The entry dated 28 July mentions Yamijima Artefact B-54 - "I cannot accept this as a proper artefact due to the possibility of forgery or a practical joke" - which is the "Annaki Remains (Claw)" found in the Mikami house's kitchen in the level "Akiko Kiyota - 15:31:58". The item, completely unfitting of the standard artefact criteria in shape and material, was something even Ryuhei Mikami couldn't accept. Also, the "Annaki remains" are one of the parts besides the bones of the Annaki, a single being that created the world long, long ago, which changed into various things. There are three times of Annaki remains in Siren 2 in total - claw, horn and fang - for details of which see the entry for archive [No.090] "Annaki". On 30 July is a mention saying, "Kanae's face resembles that of my late wife (Yayoi) to an unbelievable extent." Ryuhei most likely sensed something inexplicable connecting Kanae and his wife, who drowned in the sea surrounding Yamijima. The notebook also says, "I'm perfectly well aware that things can't go on like this." However, as he says - "I can't bring myself to do anything about it" - he also did not want to lose his peaceful life with Shu and Kanae. Contrary to his indecisiveness, 31 July's entry mentions things such as, "The window around back was broken," telling of the escalation of the discord between him and the islanders, who showed hostility towards outsiders, culminating in the tragedy on the night of 2 August. Also, on the second level of the archive, you can see a photo of Ryuhei's wife, Yayoi. From the way he keeps her photo in his notebook, you can see that Ryuhei still loves his late wife deeply. The picture shows Yayoi just before giving birth, and naturally it is Shu who is in her stomach.
[No. 081] Ryuhei Mikami's Research Notes: "Mekkoju"
A write-up of the results of Ryuhei Mikami's research regarding the "Mekkoju" (Tree of Destruction) legend that has been told on Yamijima since ancient times. The branches of the Mekkoju, a huge tree that no longer exists, are said to have the ability to "purify evil" in the legend, unique to Yamijima, which "appears to be a type of holy tree as seen in religion worldwide". Incidentally, although the Mekkoju itself no longer exists, "the head of the Ohta family goes into Mt. Shinari to collect branches (the "Mekkoju Walk"). The reason they are able to obtain branches of a tree that should not be there is a "rift" in space extending through to the World of Nothingness, which allows only the branches to pass through into the real world. Also, each person born on the island has their inscription carved into a Mekkoju branch, but this can be interpreted as something done later by people who matched it to their own values. You can think of the Mekkoju branches as having the basic ability to destroy creatures possessed by Yamirei. You could also say that Ryuhei Mikami being purified with the Mekkoju in the name of his son Shu backs this fact up.
[No. 082] Photo of Father & Son
A photo taken outside the entrance to the Mikami house in the Aonoku area. "looking for treasure with Daddy" is written on it by Shu, which is what his father's excavations across Yamijima as a folklorist must have looked like to the young Shu. The Ryuhei standing beside Shu smiling gently is a world away from the way he appears when he is destroyed after turning into a Yamibito. Also, the Mikami house entrance is where, besides being the place where Ryuhei loses his life, the adult Shu Mikami encounters his younger self, a place where all kinds of traumas converge.
[No. 083] Atlantis Special Issue: Parallel Universes
The basic thought process at the base of Siren 2's world view is the explanation of parallel worlds. To put it simply, it is the theory that countless effects of everything that happens in the universe create parallel worlds in a parallel universe. For example, whether you wash your face or do not wash your face after waking up splits the future in two from thereon. And later, whether you are late to school or not late to school causes the worlds to diverge further. Eventually a gigantic number of worlds are born, but all exist in a parallel. This is that way of thinking.