Sora Niimi is a bright, lively first-year student at Hakusen Academy and the main heroine of "9-nine- Sora-iro Sora-uta Sora-no-Oto." She is the younger sister of the protagonist, Kakeru Niimi, with whom she shares a close and often comedic sibling relationship. Outwardly social and energetic, Sora is beloved by those around her, but underneath her cheerful exterior, she's rather shy and easily frightened, particularly during times of stress—and in those moments, she yearns for her brother’s support.
Height: 156cm
Three Sizes: 82-58-77
Blood Type: B
Birthday: July 20
Sora appears friendly, talkative, and quick to make friends with virtually anyone.
Despite her outgoing demeanor, she is actually timid, somewhat introverted, and finds large group activities awkward.
She feels most comfortable in smaller, quieter circles and quickly becomes close with people once she finds common ground.
Sora teases her brother with playful banter, but their squabbles are never serious and serve as a sign of their strong sibling bond.
In reality, Sora is highly dependent on her brother’s emotional support, especially during moments of anxiety or fear.
She is resourceful, loves manga, anime, and games, and boasts a trove of niche knowledge that she keeps hidden from her parents.
Sora is the only biological younger sister of Kakeru Niimi and commutes by train from home to school each day, often accompanied by Haruka Kousaka.
She frequently visits and even invades her brother’s apartment, acting freely and often getting on Kakeru’s nerves, yet contributes to their reputation as a close sibling pair.
A heavy brother-complex (brocon) defines her affections; since childhood, Sora has loved Kakeru, showing no interest in any other boys.
She is aware her feelings are socially unacceptable and works hard to conceal them, behaving like an ordinary sister to everyone—including Kakeru himself.
However, her feelings sometimes manifest in unusual behaviors, such as creating entire photo albums of her brother, including hundreds of his sleeping faces captured on camera.
Despite her obsessive tendencies, Sora cares about her brother’s happiness—often putting his romantic relationships ahead of her own wishes.
Sora is an Artifact User.
Her Artifact, initially referred to as "Talun Kappe" and later named "Stand-Alone Complex," takes the form of a bangle.
Her ability is "Manipulation of Presence."
She can suppress the presence of a chosen target, making them unnoticeable or unable to be recognized by others.
She mostly uses her power on herself for stealth, but can extend the effect to objects within her line of sight, regardless of distance.
Her power becomes weaker if she targets multiple things at once—after four or more, it's nearly useless.
Highly resistant people or other Artifact Users, like Kakeru or Ghost, are less affected.
If Sora pushes her power to its limit, she can not only erase someone's presence but also people's memories of them, at the risk of dangerous backlash—potentially erasing herself from existence entirely.
Her stigma (the power’s manifestation point) is located below her left shoulder blade.
Kakeru Niimi: Her beloved older brother and central figure in her life. Their relationship is a blend of playful rivalry and deep affection.
Miyako Kujou: Classmate and eventual close ally; Sora supports Miyako's relationships even at personal cost.
Haruka Kousaka: Frequently seen commuting together. Sora respects Haruka and later assists her in matters of the heart.
Noa Yuuki, Sophitia, Renya Takamine: Fellow Artifact Users and comrades in addressing supernatural incidents.
Ghost and Irith: Adversaries she faces with her ability, sometimes at great personal risk.
Sora uses a wide variety of nicknames for her brother—ranging from "Big Bro" to less common forms. Even the creators lost count!
She keeps her geeky hobbies and in-depth pop culture knowledge hidden from her family.
Despite her dependence on Kakeru, she is capable and clever, particularly with internet research, news monitoring, and strategy.
She secretly creates albums of Kakeru’s photos just for herself, including hundreds of sleeping shots.
The image motif associated with her is a "cube."
"It can’t be helped that you regret killing, but… please, don’t forget that you also saved me."
9-nine- Shihaisha no Oukan
Sora’s intrusive tendencies are showcased as she frequently sneaks into her brother's apartment, sometimes even using a spare key.
After an Artifact-induced school fire, she's rescued by Kakeru and Miyako Kujou.
Once her status as an Artifact User is revealed, she joins Kakeru's investigation team, using her powers to support their efforts.
After the crisis, Sora steps aside to not interfere with Kakeru and Miyako's new relationship, showing her care for her brother’s happiness.
9-nine- Sora-iro Sora-uta Sora-no-Oto
Sora sleeping over at Kakeru’s place triggers a new set of events.
She attempts to monitor Haruka Kousaka, the "Queen of Eden," but is captured by Ghost and then saved by Noa Yuuki’s intervention.
The threat to Sora fuels Kakeru’s vow for revenge.
Sora plays a role in helping Haruka break away from Rig Veda's ideology.
She later uses her power against Ghost, temporarily erasing the enemy.
However, Sora’s ability goes haywire, causing her to be erased from friends’ and family’s memories—eventually even ceasing to exist for Kakeru.
Devastated by her imminent disappearance, Sora confesses her feelings to Kakeru. If he reciprocates, she finds peace before vanishing, causing Kakeru to lose all memory of her in a tragic bad ending.
The player can choose to reject her confession; Kakeru then saves Sora using a special elixir that cancels her Artifact contract, temporarily putting her in suspended animation.
After waking, she helps neutralize the vengeful Renya Takamine and ultimately reclaims her place in the world, patching things up with Kakeru and providing comfort for his guilt over killing Ghost.
9-nine- Haru-iro Haru-koi Haru-no-Kaze
When Kakeru suspects Ghost is the "Magic Eye User," Sora questions his reasoning.
Once Yoichi Fukazawa admits to being the Magic Eye User, Sora plans his capture, only to be overpowered by Rig Veda Asura.
She teams up with Miyako to help spike Renya’s drink with an elixir that severs Artifact contracts, and takes drastic measures in a fatal encounter against their enemies—unintentionally causing death with a special potion.
Afterward, Irith, using Satsuki Naruse's body, kills Sora, turning her to stone as part of a trap.
Using memories from alternative worlds, Kakeru and his team mount a counterattack.
With Haruka’s ability, Sora recovers and plays a crucial role in erasing Irith’s barriers, helping the group secure victory and retrieve the "Eye of the World."
Later, Sora comforts Haruka following her failed confession, gently revealing that she’s seen through Haruka's feelings for Kakeru.
9-nine- Yuki-iro Yuki-hana Yuki-no-Ato
Sora grows suspicious when Kakeru acquires memories from alternate timelines via "Overlord."
Due to Irith’s schemes, Sora acquires her Artifact powers a day earlier in this altered timeline.
She later witnesses Kakeru and Noa Yuuki in an intimate moment.
The city erupts into chaos as mind-controlled citizens run amok under Irith’s influence, and Sora helps protect her allies through her abilities.
She assists in breaking through Irith’s barriers for Miyako’s decisive blow.
Despite success, Irith resets time repeatedly, targeting Sora and leading to her death at Fukazawa’s hands in multiple timelines as Kakeru desperately attempts to save her.
Finally, through combined effort and Artifact powers acquired from other branches, Sora helps secure Irith’s defeat and celebrates with her friends once peace is restored.
Sora is portrayed by voice actress Atsumi Tanezaki in the anime adaptation.
Her Artifact ability makes her a crucial player in any confrontation involving supernatural threats.
Sora’s journey is one of courage, hidden vulnerability, and unwavering loyalty to those she loves.
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