Fuminori confesses his love for Saya, who cries, admitting she will be moving on to another world. Using a cell phone, Saya text messages him to say goodbye for the last time. Saya visits him after some time, staying on the outside of his cell where they cannot see each other. Fuminori realizes he was living as a cannibal, turns himself in, and is promptly thrown into a mental hospital. When Fuminori wakes up, he discovers his mental condition has disappeared and Saya is gone. If Fuminori accepts Saya's offer, Saya will kiss Fuminori for the last time and her tongue will slide up into his head, making him pass out. Saya then offers to change Fuminori back to normal, having figured out his condition. Fuminori witnesses the scene, and kills Yosuke in a fit of rage, afterwards consoling Saya. She ends up giving Yosuke the same mental condition as Fuminori, which results in him losing his sanity just as Yoh did, and raping Saya. Saya later tested her abilities on Fuminori's neighbor, Yosuke Suzumi, in an attempt to understand and fix Fuminori's mental condition. The reason for this action seemed to be threefold: sexual enjoyment for Fuminori, Saya's own jealousy of Yoh because of Yoh's crush on Fuminori, and was likely also a mere experiment she wanted to conduct to test her abilities. Saya even went as far to transform Yoh Tsukuba, another of Fuminori's friends, into one of her species, whose mind quickly shatters from the painful transformation. Saya and Fuminori went onto kill and eat several people including their neighbors and one of Fuminori's friends, a woman named Omi Takahata.
Later, through an odd series of events he discovered raw human flesh and organs tasted great to him, although at first he had no idea what he was eating as he found that Saya ate the same thing. Saya cooked many dishes to see if Fuminori could stand to eat since his mental condition twisted his sense of taste as well. They sent most of their time trying to figure out Fuminori's odd mental condition which seemed to be an extreme and exaggerated form of Agnosia and having an unnerving amount of sex. Fuminori and Saya became very close and they began living together after Fuminori was discharged from the hospital. The catch was that he saw everyone else as a horrific monsters and the whole world as hellish landscape of blood, gore, and monstrosities. Fuminori had survived a near fatal car accident and because of a new experimental operation that saved his life he saw and heard Saya as an ordinary human girl. It was during one of these scares that Saya met Fuminori Sakisaka. She spent her time searching for information on her father and entertaining herself by scaring patients at night with her grotesque image. Saya lived within the hospital Fuminori was in at the time, feeding mostly on cats, other animals, and supposedly a human infant. She survived on her own for a while until she decided to go out and find what happened to her father who worked at a local hospital.
Ogai mysteriously disappeared after going to work, leaving Saya alone. Afterward, Ogai and Saya moved to his personal home in a Japanese suburb until Dr. Her avid reading habits had made her develop human-like emotions and almost like a child first understanding love she wished for it. Ogai began care for Saya deeply and in his journal he mysteriously wished in anguish that if only someone could find his daughter beautiful and give her affection as Saya began wanting deeply love and acceptance. Ogai then gave the creature a name, 'Saya', which was the name of one of his childhood pets. Ogai started referring to the creature as his daughter and the creature referred to him as its father. Shortly after the creature started this trend, Dr. Ogai was quite surprised to find that the creature had an overwhelming passion for human literature and after reading through many novels the creature first started showing or developing signs of being feminine. Oddly though, the creature swiftly got bored and moved onto to other things. The creature showed signs of intelligence beyond human understanding as she was able to break many mathematical algorithms that no human or even computer had been able to break. Saya initially lived with Ogai as he did many experiments on her to determine what exactly he brought into this world. Although, the lines between the occult and science are blurred at times when Ryoko Tanbo starts reading Dr. It is more hinted that Saya was brought into this dimension by occult means rather than science due to the interaction with the character Ryoko Tanbo who had been hunting Dr. Ogai used to bring the creature that would come to be known as Saya is unclear and shrouded in mystery.
Masahiko Ogai, a Japanese doctor working for the Tokyo University Hospital system. Saya was brought into this world via the experiments of Dr. Spoiler warning: Plot and/or ending details follow.