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Fanfic / Kaiens Fate Aizens Experiment And Ichigos Sister

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Kaien's Fate, Aizen's Experiment and Ichigo's Sister is a Bleach fanfic by SeerKing where Aizen used Kaien's reiatsu in a number of experiments, and the only survivor managed to escape to Karakura Town and be adopted by the Kurosaki family.

Shiba Kaien died at the hand of Kuchiki Rukia after being possessed by a Hollow. This is well known. What if Aizen drew Metastacia from Hueco Mundo and extracted some reiatsu belonging to Kaien for another experiment? This is the tale of the result of that experiment; Kurosaki Kirika.


Kaien's Fate, Aizen's Experiment and Ichigo's Sister provides examples of:

  • Absence of Evidence:
    • One of the things that Kirika points out about Aizen's "murder" to Toshiro is that no one noticed it while it was happening. Considering how powerful Captains are, it should be nearly impossible, if not entirely so, to keep anyone from noticing the Riatsu or sound of such a clash, especially since his own sword "killed" him. So how come no one knew about it until they found the "body", well after when he supposedly died? There's also the fact that the Ryoka simply lack the ability to have dome it given their current power levels.
    • Kirika has been using Hakuda against the Onmitsukidō, almost exclusively, if not entirely so (like her teacher Yuroichi), so the lack of any signs of it having been used on the body of the member Gin killed with a slashed throat to hide their meeting, despite her beating a group of them that way not far from the scene, tips the Captains off to the involvement of a third party in play when combined with the above.
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    • The absolute lack of any communications between the Central 46 and their families despite the lockup is one of the things that tips Hitsugaya off.
  • Afraid of Their Own Strength: Hisagi's philosophy, which actually causes Kirika to burst out laughing when she hears it. She then tells him that while fearing not having enough power to achieve one's goals, a lack of control getting someone hurt, and/or using power for the wrong reasons are valid, fearing one's power just for the fact that it exists is foolish because it would forever limit her growth, since she'd be stepping back in fear every time she tried to progress. This makes Hisagi realize that his fear keeps him from materializing his Zanpaktou spirit whenever he tries to learn Bankai.
  • Alliterative Name: Kirika Kurosaki.
  • Almighty Janitor: Lampshaded when the group learns that the Co-3rd seat of the 4th Division is doing janitorial duties.
  • Badass Gay:
    • Yuroichi and Soi-Fong.
    • Kirika is also hinted to be attracted to women, namely Tatsuki.
  • Bare-Fisted Monk:
    • Yuroichi's focus on Hakuda is revealed to be partly because she can't carry her sword in werecat form (not to mention it not being exactly an assassin's tool), and a preference towards fighting with only Hakuda with the Onmitsukidō. It certainly helped that she usually didn't use it when she was still with Soul Society unless she was punishing someone.
    • Kirika herself tends to default to Hakuda while rescuing Rukia, since she was the above's student in that regard, especially with the Onmitsukidō.
  • Big Sister Instinct: After her adoptive mother's death, Kirika became potentially even more protective of her siblings, Ichigo included, than Ichigo is to Yuzu and Karin in canon. She actually threatens to kill Urahara if his schemes cause any permanent harm to Ichigo, and the rest of the Shoten crew thinks she might actually be able to follow through on it.
  • Boxing Lessons for Superman: Kirika plans to give Ichigo these when they return to the World of the Living.
  • Confusion Fu: Kirika's sword style combines elements of several other styles, to the point that Hisagi can barely recognize it as Zanjutsu, and notes that even Zaraki (whose "style" is "hack and slash") isn't as random as she is. He even comes to the conclusion that the entire point is to be unpredictable and take advantage of the openings made when her foes misjudge how to react.
  • Contrived Coincidence: Kirika only survived because her potential Zanpaktou was of the same type as Kaien's own, a Flowing-Water type, and they thus managed to integrate with each other. She even lampshades how her survival was sheer luck.
  • Cover-Blowing Superpower: Kirika's Zanpaktou could be recognized as Kaien's if she used it, so she can't use its Shikai when rescuing Rukia without blowing her cover to Aizen. Not that she has much trouble regardless.
  • Dark and Troubled Past: Kirika was kidnapped when she was an infant, subjected to over three years of twisted experiments, up to and including apparently being repeatedly vivisected, watched the other prisoners she had befriended either turn into Hollows or commit Soul Suicide, and only escaped being disposed of thanks to Gin.
  • Death of Personality: Preventing this is why Urahara and Tessai sealed Kaien's memories.
  • Dirty Business: Kirika isn't exactly happy about using her brother and friends to sabotage Aizen's schemes. Urahara's insistence on secrecy and only keeping her in the loop the bare minimum he can due to worries that she's part of some Long Game Aizen is playing hasn't exactly helped.
  • Everyone Can See It: Kirika finds Orihime's attraction to Ichigo obvious.
  • For Want of a Nail: The nail being Kirika's survival and adoption into the Kurosaki family.
  • Ghost Memory: Kirika inherited a good chunk of Kaien's memories, but most are sealed out of fear that they'd overwhelm her and essentially turn her into a female Kaien before her ego could sufficiently develop. Some do leak through from time to time though.
  • Hard Light: Senataro's Shikai blade is made of this, which renders the weight-doubling Wabisuke useless against it.
  • Honesty Is the Best Policy: Kirika repeatedly advocates this in regards to Ichigo, only to be outvoted.
  • Imagination-Based Superpower: Sentaro's Shikai allows him to create Hard Light constructs like a Green Lantern. The catch is that since it's based off of his artistic abilities, it looks like a three-year-old drew them.
  • Internal Reveal: In chapter 18, the rest of the group learns the truth about "Kokken Asa"/Kirika being one and the same, and Aizen learns that his former test subject survived.
  • Keeping Secrets Sucks: Kirika doesn't really like Urahara's insistence on secrecy, having been outvoted every time she's suggested bringing Ichigo more into the loop. She also hates having to keep up her "Kokken Asa" persona and plans to come clean after Rukia is rescued and it won't be a distraction.
  • Lethal Chef: Apparently Urahara can't make anything more complex than instant noodles to save his life.
  • Logical Weakness:
    • Itegumo's An Ice Person abilities are not effective against Tetsugumo's clouds since it can't generate enough cold to freeze a gas.
    • Wabisuke's Shikai is useless against the Shikai of Sentaro's Senkomaru, since it's power is Light 'em Up (its blade being lightsaber-like Hard Light). After all, photons have no mass, and no mass means no weight, so Wabisuke's ability to double the weight of whatever it hits is useless. Zero doubled is still Zero, after all.
  • Make a Wish: The Hōgyoku reacts to Rukia and Kirika's wishes as Aizen is removing it from the former.
  • Mama Bear: Yoruichi develops a bit of a maternal streak towards Kirika.
  • Meaningful Name: Kirika's name means "Mist Fire", for the mist of her memories and her fiery hair.
  • Not So Different: When thinking about how Aizen will probably wait for everyone to be too wounded or tired from the battles before making his move, Kirika notes that it's what she would do in the same situation. She's more than a little disturbed at how easily she can get inside Aizen's decision-making processes.
  • Not So Invincible After All: Aizen's plans not only get disrupted by Kirika several times, but she actually manages to hurt him a couple of times, in albeit minor ways, though she does leave him with a permanent scar on his torso.
  • Oblivious to Love:
    • Kirika herself notes that Ichigo tends to be dense when it comes to things like noticing Orihime's feelings for him.
    • Yuroichi took a century to ask Soi-Fong out... right before Aizen's Frame-Up.
  • O.O.C. Is Serious Business:
    • Aizen actually displays noticeable frustration when Gin reminds him of a meeting he has with the Captain Commander and is irritated by Kirika/"Kokken Asa" being a Spanner in the Works. When she hits him with a fire Kido after he teleports in, he is noticeably pissed off and tells Gin to kill her, and in the next chapter, Rukia notes that she caught a glimpse of surprise on his face before the fire hit.
    • Tosen actually snaps at Gin at one point.
    • One of the things that tipped Hitsugaya off the fact that the Central 46 had been subverted was how they were not only outright breaking their own laws, instead of using Loophole Abuse like they normally do, and how the Kuchiki family representative was drawing attention to Rukia's actions, but that none of them were communicating with their families.
  • Playing with Fire: Kirika has an affinity for fire Kido.
  • Psychic Block Defense: Kirika has a unique ability to keep any foreign influence out of her Inner World.
  • Rational Fic: Is it really any surprise, given the author?
  • Reality Ensues:
    • Kirika has some major Survivor's Guilt regarding her friends from Aizen's experiments. Part of why Urahara gets the Kurosakis to adopt her is to help her recover and keep her from going off and doing something stupid. She herself notes that it's amazing that she has no nightmares of that time.
    • Urahara's habit of keeping secrets bites him in the butt with Kirika, who is tired of being Locked Out of the Loop for a lot of his plans (in part because part of him still worries that she's part of a plot by Aizen) and not being allowed to tell Ichigo and company what she ''does'. She outright threatens to mostly cut ties with him after Rukia is rescued, and tells him that she'll kill him if he hurts Ichigo with his experiments (something the other Shoten members think that she might actually pull off). Even his friendship with Yourichi starts to fray.
    • Aizen, while a skilled Chessmaster, can't account for everything, especially an Outside-Context Problem. Kirika's involvement throws him for a loop because he thinks she's dead and doesn't have any solid info on her Kokken Asa persona.
      • He also focused on the higher ranked Soul Reapers (3rd Seat and above) when hypnotizing people, assuming that no one below those ranks could pose a serious threat (presumably, he also had pragmatic reasons for not just being able to hypnotize everyone), so Yumichika's true power level surprises him.
      • He also is not immune to being caught off guard and injured. Kirika hitting him with a fire kido right as he shows up, having expected him, actually does some damage, for example.
  • Revealing Cover-Up:
    • Gin kills an Onmitsukidō member to cover up his and Kirika's talk. But the way he did it, slashing his throat, tips the Captains off to someone else working behind the scenes, since Kirika/Kokken Asa, like her mentor Yuroichi, has previously used only Hakuda against them, and it would be weird for her to change methods so suddenly, especially after defeating a group of them that way fairly close to that location.
    • With Kirika around to point out how weird it is that no one noticed Aizen's "assassination" until well after the fact, the other Captains are starting to ask questions.
  • Scars Are Forever: Kirika is able to slash Aizen across the chest before he can escape with the Hogyoku, and even after it's healed it will leave a scar.
  • Secret Identity Vocal Shift: Kirika as "Kokken Asa", thanks to her mask.
  • Secret Keeper: Besides the Urahara Shoten crew, only Ishida has any idea that Kirika is "Kokken Asa". She gets him to keep quiet about it during the invasion by giving him information on Mayuri.
  • Shapeshifting Excludes Clothing: Why a certain werecat never really uses her sword. Kirika offering to carry it for her when needed bypasses this issue.
  • Sink-or-Swim Mentor: Ganju all but drops the trope name regarding Yoruichi.
  • Smug Super: Aizen is genuinely powerful and skilled, but he tends to underestimate his foes.
    • He never thought that anyone below a Third Seat could come close to being a problem for them, so he left them out of his hypnosis targets, and never got the recently promoted Hanatarō because he fell into the trap of looking down on Squad 4.
    • He never learned any healing Kido above a mid-level one, and that only because of thoroughness, because he never thought that anyone would actually be able to hurt him save Yamamoto (at which time he'd have unlimited regeneration(, so he's unable to fully heal the wound Kirika gave him.
  • Sole Survivor: Aizen used over half a million souls in his experiment, and Kirika alone survived, and only because she had a potential Zanpaktou of the same category as Kaien's.
  • Spanner in the Works: Kirika ends up making things more troublesome for Aizen than in canon because he has no idea that his former experiment is alive and knows about him, or that she's the mystery Soul Reaper with the Rukia rescue party. For example, capturing Momo right before he fakes his death, preventing her mental breakdown from distracting her companions, and pointing out the discrepancies in his "murder".
    • Earlier, Urahara forgot to account for Kirika's effect in the spiritual growth of Ichigo and his classmates.
    • Later, Aizen expresses the belief that the only reason his plans still have a chance is the ossified nature of the Gotei 13.
  • Stylistic Suck: Sentaro's Hard Light constructs due to his poor art skills.
  • Suicide by Cop: Nejibana confirms in the latest chapter that Rukia was able to kill Kaien because he managed to retain just enough control over his body, and enough affection for her, that he was able to let her strike the fatal blow.
  • Surrounded by Idiots: Yamamoto is of the opinion that the rest of the Captains wouldn't be able to organize a flea market without him cracking the whip and keeping them in line, which is why he hasn't retired yet.
  • Training from Hell: Kirika's training involved getting her ass kicked repeatedly by three Captain Class Soul Reapers, but the results are undeniable.
  • Underestimating Badassery: Aizen has a habit of doing this, assuming that his foes cannot do anything to him.
  • Weak, but Skilled: Kirika lacks her adopted brother's overwhelming amount of raw power but makes up for it with superior skill with swords, Kido, Shunpo, and Hakuda.
    • Sentaro is Lieutenant level but still counts with his use of a weak binding Kido to keep Kira's more powerful Blow You Away Kido from lifting him off the ground. Even Kira has to admire the creativity of the technique.
  • Wise Beyond Their Years: Kirika, partly as a result of both what she went through at Aizen's hands and her inherited memories from Kaien. Yoruichi even lampshades it, saying that she's got everyone in the rescue group except maybe Chad beat in the emotional maturity department.
  • You Are Number 6: Kirika's name was given to her by her fellow prisoners, as she was abducted as little more than an infant and couldn't remember her original name, and Aizen and co referred to her via this trope.
  • You Fight Like a Cow: Kirika often insults her opponents to get them mad and keep them from fighting at their best, at least in her "Kokken Asa" persona.


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