Shiro Onijima

Shirō Onijima is the father of Utsutsu Hasegawa and Yume Hasegawa. He is a deranged abusive man who belongs to a secret organization.

Appearance
His usual attire is a formal black suit. He has short black hair and black eyes with glasses. However, it's debatable if he can see without them, since as a child and teenager he was seen without them. "Maria's Island" reveals that his body is covered in lashes and scars from Genjurou's abuse on him.

Personality
When he was young, Shiro was a scared little orphan who was aware that his mother didn't want him and was afraid of Genjurou. After being abused and tortured by Genjurou all his childhood, Shiro ended up deluding himself that the abuse was Genjurou's love for him. He even admits himself that he doesn't know how to show proper love to others.

Now as an adult, Shiro is a deranged and abusive man that resolves everything with violence. He enjoys beating up his children, especially Utsutsu, and previously his own wife. He is the kind of stubborn man who get's a 'kick' out of terrorizing others. He believes that he can do what he wants, and that Utsutsu belongs to him only.

It's revealed that he was abusive towards his wife and son because of a misunderstanding. He was aware that Yume wasn't his daughter, but since at the time he didn't know about the Pupa virus, he believed that Sachiko betrayed him. Shiro actually cares about Utsutsu in his own twisted way and wants to "break" him just like Genjurou abused him in his childhood. He loves Utsutsu very much, but he's dismissive and hateful towards everyone else. He doesn't like Yume for stealing his son's love and calls her a "fake sister".

Background
As a young child, Shiro was an orphan adopted by  Genjurou Imari, Maria's grandfather. For years he was locked in his house, physically abused and used him as little more than a toy. Genjurou often whipped him, just for the sake of inspiration for his paintings. He was forced to live inside a cage, naked and didn't even have a proper name, as Genjurou labelled him "Earthworm" and didn't see him as a human being.

Years later, Genjurou commited suicide, and Shiro was rescued. At the funeral, he met Genjurou's granddaughter, Ai Imari. She convinced the traumatized boy that Genjurou's abuse was his love for him and told him that other orphan boys had been abused like him, but they had died from the torture.

After Genjurou's death, Shiro could not live a normal life after all the abuse he had gone through, so he joined a mysterious organization, where he could use his strength and endurance. He became violent and unhinged, believing Ai's words: that violence is the greatest form of affection.

Manga
At first, Shiro is introduced as the abusive patriarch of the Hasegawa family and was the one who gave Utsutsu the scar across his eye. He is shown to care about Utsutsu somehow, such as searching for him and Yume after they're kidnapped. However, the first thing he does upon reuniting with him is to warn Utsutsu about Yume and to give him a beating after he doesn't listen.

After Utsutsu and Yume are on the run, he decides to pay his ex-wife Sachiko a visit, to know more about the Pupa virus. However, since she freaks out upon remembering the awful truth about Yume, the doctor Chiharu Bizen proceeds to explain Shiro the truth. It turns out Shiro and Sachiko married after she was pregnant and he was actually excited to be a father. However, he had to go to work overseas and left the pregnant Sachiko.

Also, Yume is actually a monster that was created in a laboratory. She escaped the laboratory and entered Sachiko's uterus. The monster had the ability to mimic, so once inside of Sachiko, she had copied everything about her host-mother. Thus, resulting in Yume having the exact same DNA as Sachiko. When Shiro came back from overseas, he was very angry when he saw the was another child besides Utsutsu. Believing that Sachiko betrayed him, he started becoming abusive towards her as a result. Sachiko shortly abandoned the house, because she was creeped out by Yume, because she was aware the child was a monster. When Utsutsu demanded to know why their mother abandoned them, Shiro lied to him, by saying that she was seeing another man.

With this knowledge, Shiro, together with his partners Haruka and Ryuichi, goes looking for Utsutsu and Yume (who is stuck in her monster form) again and finds them hiding in a forest. After beating Utsutsu once again, Yume goes into one of her rampages again. Shiro continues to beat Utsutsu, claiming that he does that because he loves his son very much, which is confirmed after some flashbacks about Shiro's abusive childhood, with his captor convincing him that pain was love. Suddenly Utsutsu slowly starts mutating into another Pupa monster and calls out his father for his distorted vision of love and impales him with a tentacle, fatally injuring him. However, Shiro survives the mortal wound.

When Yume calms down and returns to her human form, Shiro carries the unconscious Utsutsu to safety as he tells Yume that she should stop calling him "brother". Just then, Maria appears, having impregnated with the Pupa Virus and turning into a flesh blob. She kidnaps Yume in an attempt to assimilate with her, absorbing Utsutsu, Shiro, Haruka and Ryuichi in the process. When Utsutsu wakes up, he realizes that Yume is gone. Utsutsu has accepted that Yume is not his real sister and is a monster, but as he rationalizes it, he is transported to the bottom of Maria-Yume's monster form.

Shortly, Utsutsu gets out of Maria, after coming to terms with the truth about Yume. However, this is too much for him and becomes a monster. Shiro watches helplessly and starts calling out his son in vain. It's revealed that Utsutsu didn't mutate into a monster, because he was already one. After Sachiko abandoned them as children, Utsutsu became very depressed, so Yume went out in the streets to search for Sachiko. However, she didn't see an incoming truck on the way. Utsutsu, who was searching for her, protected her with his body, but ends up getting himself killed instead. As it turns out, Yume didn't need protection because she could easily regenerate from her injuries and feed the dying Utsutsu some of her flesh, so he could revive as a monster and became imprinted to her.

After Utsutsu and Yume dissolve into red butterflies and fly into the distance, Shiro looks at the scenary helplessly, since in the end he was unable to save Utsutsu.

The "Maria's Island" afterstory shows everything about Hotoki's past with Maria, revealing that they knew about Shiro being locked and abused by Genjurou, but Maria didn't care and Hotoki, although feeling sorry for Shiro's abuse, he believed he didn't have to pry into his grandfather's issues. When Genjurou commits suicide, Maria tells Shiro that he wasn't his first victim and Genjurou had been torturing other three orphan boys in the past. However, all they died from the torture. If Genjurou might have lived longer, Shiro would have died from the abuse. After Maria convinces him that the abuse and torture were Genjurou's love for him, Shiro breaks down crying.

Anime
Because the anime was short, it only covers the first part of the manga, when Yume transforms into a monster and she goes berserk after Utsutsu is dissected alive. Shiro is portrayed as an abusive father. The fact that he is affably evil and he actually cares for Utsutsu are left out.

Trivia

 * He was born on April 6th (on the family register).
 * His blood type is A.
 * His favorite food is Sweet bean jelly while his least favorite is Kazunoko.
 * He also seems to be a fan of Sylvester Stallone since his ringtone is the Rocky theme.
 * Shiro Onijima isn't his real name, as he was a nameless orphan and Genjurou never bothered to give him a proper name. He started using the name after escaping from Genjurou.
 * "Maria's Island" reveals he's actually younger than Maria, but looks older in the present time due to his lifestyle.