Mamiya Hasaki

"How convenient. ...In other words you treat me like your sister when it's convenient, and like a stranger when it's not."

- Mamiya Hasaki, Jabberwocky I

Mamiya Hasaki (間宮 羽咲) is the protagonist of the Which Dreamed It chapter. The timid little sister of Mamiya Takuji. She always carries around a stuffed rabbit doll with her. She is the only one left to remember a certain past incident.

Appearance
Hasaki is a young girl who looks about 12 - 14 years old. She has light brown hair and teal green eyes.

She doesn't attend Kita High, so she's often seen wearing the uniform of another school. The uniform consisting of a white shirt, green tie, beige vest and pleated skirt.

For her casual outfits, she wears light blue pajamas and shorts as sleepwear. As a kid, she wore a flowy white dress. She also wore a one-piece swimsuit with skirt like bottoms, and an illustration of a bunny eating another bunny's head on it as a kid.

Personality
Hasaki is a shy, but eccentric girl. She's deeply attached to her brother Tomosane, and constantly tries to get his attention and grow closer to him.

She has a low self-esteem due to how she was mistreated and abused by Takuji and her mother, and she considers the misfortune that befell everyone her fault.

Despite her shy nature, she can be quite assertive and forceful when she wants to. Taking down Kimura when she found out he was investigating Tomosane, and holding on to Tomosane when he's about to fall off the roof at the very end of Which Dreamed It.

She can also be emotional and short-tempered, getting annoyed at Tomosane and yelling at him whenever he tries to avoid her and tries to annoy her to chase her off.

Plot
Hasaki is the twin-sister of Mamiya Takuji and the half-sister of Mamiya Tomosane, born the child of Sanami Kotomi and the founder of the White Lotus Association. She was an unwanted child, since the prophecy of the founder only told of the birth of one child. The founder uses this as an excuse to get rid of Kotomi, who he was just using.

This leads to Kotomi and Takuji constantly abusing Hasaki, believing her existence to be the barrier between Takuji and his savior powers, Tomosane being the only one who stands up for her. Soon enough, Tomosane gets sent away to Sawaimura due to an incident with Kotomi, and eventually, Hasaki moves to Sawaimura too,

There, she meets Minakami Yuki, and grows close to her and Tomosane, with the three of them often hanging out together.

One day, she spots a rabbit doll through a store window, which she instantly becomes enamored with. Seeing this, Tomosane wants to get the doll for her but it ends up being too expensive. Over the next few months, Yuki and Tomosane go to the store regularly to get measurements from the doll so they can sew her one themselves. When Hasaki receives the doll, this becomes an extremely precious memory to her, and the doll itself becomes a representation of her younger self, a time when she was at her happiest.

Soon enough however, the already ill Mamiya Hiroo dies. On the day of his funeral, Hasaki runs away alone to the hill of sunflowers, believing she could catch his spirit and stop him from leaving if she climbed that hill, but with her small body, she can't, and Tomosane carries her home.

The next year, on the anniversary of his death, Takuji and Kotomi show up, despite not coming to the funeral. On the day of the anniversary, Hasaki, Yuki and Tomosane climb the hill of sunflowers at last, Yuki and Tomosane talk while Hasaki goes off to play. Unexpectedly however, Kotomi and Takuji show up, attacking Hasaki and holding her at knife point. In the ensuing struggle, Hasaki falls of the cliff, but is saved by Yuki, who jumps after her, holds her, and takes the fall for her, but this results in Yuki's death. Tomosane ends up accidentally stabbing Takuji in a struggle, resulting in his death as well. Hasaki, Tomosane, and Kotomi, broken by the death of Takuji, are the only survivors of the incident.

Hasaki is mentally and physically scarred by this incident. Tomosane, who is just as traumatized, develops DID as a result of PTSD and erases his own personality, creating Yuki and Takuji as alternate personalities within him.

Years pass by, and the Tomosane personality eventually returns as Yuuki Tomosane, though this Tomosane has no memories of his past and pushes Hasaki away in fear of hurting her when he's erased.

Eventually, the Savior awakens within Takuji upon Takashima Zakuro's suicide, and the time for Tomosane to fulfill his role comes. After Tomosane heads off to face Takuji for the final time, Hasaki secretly follows him alongside Kimura. When she sees him pointing a knife to his own chest, she tries to stop him, but the fight results in Takuji's win, and Tomosane's death.

When Hasaki follows after Takuji and tries to confront him, Takuji, seeing her as the Wakatsuki sisters, orders his followers to rape Kagami, who is Hasaki's rabbit doll. Seeing a representation of her happier, younger self violated breaks Hasaki.

On July 20th, Hasaki is lead to the rooftop by Ayana, where she sees Takuji about to jump, just as he does, she grabs on to him. At this time, Tomosane is awakened inside his body once again, and he and Hasaki fall together, depending on the ending, they either survive, or their fate is unknown.

Wonderful Everyday
Wonderful Everyday is essentially Hasaki's route. Hasaki and Tomosane enjoy a somewhat normal life together despite all the repercussions of the incident at Kita High on July 20th. Hasaki comes to sympathize with her mother and her actions, why she did what she did, and more. Tomosane lets it slip to Kimura that he is actually in a relationship with Hasaki now.

Hill of Sunflowers
Hasaki and Tomosane head back to Sawaimura. Yuki makes her return, with Hasaki and Tomosane both being able to see her as a ghost-like figure now, with all three of them reunited, they go back to live a happy life from then on.

Knockin' on Heaven's Door
Hasaki is only referenced throughout Knockin' on Heaven's Door, and never directly shows up, but she's said to be away at university.

Yuuki/Mamiya Tomosane
Mamiya Tomosane is Hasaki's older half-brother. He was the only one who stood up for Hasaki ever since she was a child, and protected her from Takuji and Kotomi's abuse. When Hasaki moves to Sawaimura, Tomosane promises to be her hero, and even makes her a rabbit doll they couldn't afford from scratch to make her happy, a rabbit doll which she grows to treasure dearly.

When Takuji and Kotomi make an attempt on Hasaki's life, and Takuji is killed, their life changes forever. Tomosane developing DID and his original personality erasing itself. When he comes back as Yuuki Tomosane, he keeps trying to distance himself from her to avoid hurting her when he dies. At the end of Jabberwocky, he finally gives up on the act and admits that he does care for her. In the Wonderful Everyday route, he also realizes that he has feelings for her.

At the end of Jabberwocky II, he reawakens, determined to save Hasaki, as they both fall from the roof of Building A. In the Wonderful Everyday ending, both of them survive and start living a somehow normal and happy life together, becoming a couple.

Minakami Yuki
Minakami Yuki was a good friend of Hasaki, almost like a big sister to her. Taking Hasaki and Tomosane to places, helping Tomosane make the rabbit doll for her, comforting her when her father died, and even sacrifing her life to save Hasaki, showed how much Yuki truly cared for Hasaki.

When she comes back as a personality inside Tomosane, she still deeply cares for Hasaki, and often teases her about her feelings for Tomosane. She repeatedly emphasizes to Tomosane that he needs to stick around to protect Hasaki, and is the one to encourage him to go be her hero, and save her at the end of Jabberwocky II.

They often have playful fights over Tomosane, but get along well.

Mamiya Takuji
Takuji harbors a deep dislike for Hasaki. Brainwashed by his mother since childhood into believing that Hasaki was the obstacle keeping him from gaining his savior powers, he constantly abuses her, and eventually makes an attempt on her life.

When he comes back as a personality inside Tomosane, he still deeply hates Hasaki. He sees her and her doll as the Wakatsuki twins, and instinctively hates them because of this, going as far as to have her doll raped and crucified in front of her.

Kimura Nobukatsu
Kimura is a journalist Hasaki meets when he's investigating Tomosane. Though they get off to a bad start, soon enough, he begins helping and supporting Hasaki alongside Master.

Eventually, he learns of the truth behind the incident years ago, and encourages Hasaki to act, and tries to tell her none of what happened was her fault. When Tomosane's personality finally comes back after being absent for a long time, he immediately conveys Hasaki's message to him.

He also accompanies Hasaki to Kita High when she follows Tomosane as he heads off to have his final fight with Takuji.

Sanami Kotomi
Kotomi despised Hasaki, and considered her the reason why Takuji couldn't gain his savior powers. She manipulated Takuji into trying to kill her as well.

When this attempt fails, and Takuji himself is killed in the process, Kotomi begins acting like Tomosane is Takuji, and even legally enrolls him into school under the name "Mamiya Takuji". Eventually, she ends up in a catatonic state, with Hasaki being her only caretaker.

In the Wonderful Everyday ending, despite all the suffering Hasaki went through at Kotomi's hands, she chooses to see her with compassion, as a pitiful woman who was just trying to do what she thought was right.

Otonashi Ayana
Ayana appears to Hasaki at the end of Which Dreamed It, as an inhuman and mysterious figure that leads Hasaki up to the "End Sky", to the Building A rooftop Takuji is about to jump from.

Trivia

 * Tsukasa being the "little sister" type, and the sister of Kagami, represents how Hasaki is Tomosane and Takuji's little sister.