Automatic Purification System

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The Automatic Purification System (自動浄化システム, Jidou Jouka Shisutemu) is a phenomenon that occurs within a field in Kamihama City, which prevents Magical Girls from becoming Witches in the universe of Magia Record, and releasing Doppels instead.

The core of the Automatic Purification System, the Magia Record, is a conceptual space that can be accessed by bringing all eight Kimochi together. This space can be tied to a specific person, and the status of the APS is directly linked to the life of that entity, ultimately ending up with Iroha as host, as well as Ui, Touka, Nemu, Lil' Kyubey and Sakurako as inhabitants, or "organs." If the core's host is taken out of commission, the Doppel System may malfunction, lose efficiency and even fail completely.

Game

Creation

The Doppel phenomenon resulted from Ui Tamaki, Nemu Hiiragi, Touka Satomi and Alina Gray's combined efforts. To save Iroha Tamaki, Touka, Nemu and Ui planned to steal Kyubey's powers through their wishes and prevent Magical Girls becoming Witches.

Ui wished for the power to collect, or harvest impurities, which would be used to collect the impurities of Soul Gems. Touka wished for the power to convert, or transform, which allowed her to convert energy from one form to another. This power would then be used to convert the impurities into magical energy which would then be released as phase shift energy into the universe, just as Kyubey intended. Lastly, the energy would be passed to Nemu, who wished for the power to manifest, or materialize, which would manifest the energy into an expanding field of an Automatic Purification System. This process allowed the three girls to create a system which would still allow them to combat entropy, while not having Magical Girls turn into Witches.

After they made their wishes, the Incubator to whom they made their wishes lost its rings and turned into a smaller form after it had most of its powers taken away and was disconnected from the network. Quickly after, Ui quickly became overwhelmed by impurities, risking turning into a Witch herself, until Alina Gray used her barriers to isolate her, buying them more time. Nemu then used her powers to create an Uwasa which put Ui's soul into the Lil' Kyubey to keep it safe. This transferal caused all traces of Ui to be erased, including all physical records and memories of her.

What remained of Ui's body turned into Embryo Eve, an unstable "half-Witch," that absorbed impurities from Soul Gems right about when they were to turn into Grief Seeds. Alina then expanded the field she'd formed around them to encompass all of Kamihama City, making the Magical Girls within the field release Doppels instead of turning completely into Witches.

Inside the Doppel Field, the curse unleashed when a Soul Gem becomes a Grief Seed instead manifests into a part of the user's body, then usually fades away soon after. Nemu's powers modified the field to also block all Incubators from entering, having them lose consciousness the moment they entered, with the exception of the Lil' Kyubey containing Ui's soul, as it was separated from the Incubator network. The Doppel System however releases a lower amount of energy as compared to the previous, Witch System.

The system's core needs a viable inhabitant, such as someone involved with its formation, either Lil' Kyubey, or Ui herself. Embryo Eve's body used Ui's soulless body as a core in order to keep itself stable, and Touka, Nemu and Alina formed the Wings of the Magius to expand the Doppel System by feeding Embryo Eve. They would then spend many months feeding energy collected by Nemu's Uwasa, as well as living Witches, Grief Seeds and the impurities Eve and her Familiars collected.

The Wings of the Magius' base of operations was the Uwasa of Hotel Fenthope, with the place where Eve was chained up to being a golden Magius symbol pillar in the center of the Hotel's chapel. Soon, the impurities Eve absorbed made the environment difficult for most Magical Girls to stand and only the Magius themselves would usually frequent there.

Arc 1

The escalating conflict between the Wings of the Magius and Kamihama's resistance culminated in an assault on Hotel Fendthope, the Magius' headquarters, where the Magius had planned to sacrifice many girls' Soul Gems as food for Eve. With Walpurgisnacht approaching, Touka and Nemu planned to have Eve consume her and use the collected energy to spread the Doppel barrier around the entire world. However, this fusion would create an explosion strong enough to wipe Kamihama off the map.

During the confrontation, Iroha recognized Eve as her sister, Ui Tamaki, after a cherry blossom branch from the Rumor of the Ten Thousand Year Sakura bloomed upon contact, confirming their reunion. She was eventually able to break Ui out of Eve's body and return her soul to her, also restoring the traces and memories of her existence.

Alina Gray, still seeking to weaponize Eve's unstable body for her "art," seized control using the Rumor of the Fur God to suppress Eve's will. She wrapped the barrier around Kamihama onto Eve's body to keep it stable, and used the Fur God to steal her freedom, as Eve lacked a conventional form of life.

Nemu sacrificed her remaining lifespan to summon her Uwasa against Alina, destabilizing Eve's form. With Ui extracted, but Eve still active, Lil' Kyubey merged with Eve, becoming the system's new core and stabilized the purification field, though its reach remained confined to Kamihama. As the small Kyubey fused with Eve, several entities were ejected from Eve's body and landed on different parts of Kamihama, though they wouldn't be encountered until later.

Later on, after the fight against Walpurgisnacht, Touka, Nemu, Ui, and Iroha visit the Eternal Sakura together, where the Rumor points out that the Little Kyubey had been waiting for some time, ready to join them again.

Arc 2

In Kamihama, eight creatures called the Kimochi appeared. These beings were the crystallized emotions of Eve, which had escaped her body when Lil' Kyubey replaced Ui as its core, as Incubators don't have emotions. The Kimochi sought to fuse back with each other and Eve's core, and the person who controlled all the Kimochi and the core would be able to control and spread the Doppel Field's reach across the world.

While conflicts over the Kimochi developed in Kamihama, after Lil' Kyubey had left the core unattended, Kyubey was able to eventually take control of it due to its connection to Lil' Kyubey. An Incubator, lacking emotions, was also able to work as a host, and Kyubey was able to turn off the Doppel Effect, as he'd judged that the Witch System was still more efficient than the Doppel System.

After the faction leaders had reached an agreement, they joined the Kimochi stones and gained access to the core's realm. Once the core manifested however, Kyubey was even able to teleport it to different parts of Kamihama to keep it out of others' reach. Kagome Satori made a contract to keep Kyubey away from the Automatic Purification System permanently, but before they could fix the system, Mikoto Sena used Winchester's powers to block the core by forming a barrier around it and all of Kamihama.

To fight Winchester and save the Magical Girls of Kamihama, Iroha, Ui and Lil' Kyubey fused the Kimochi stones with the core, fusing together and becoming Infinite Iroha, the core of the Doppel System herself. Using Infinite Iroha as the power source, Touka and Nemu had also turned themselves into the Uwasa Queens to help in the system's maintenance, as well as turning the Magical Girls of Kamihama into Uwasa to save them from becoming Witches.

After Mikoto's defeat, she also fuses with Iroha and gives her access to the Endless Mirrors Labyrinth, allowing Iroha to travel through space and time. Iroha used her Reversal magic to restore the girls back into Magical Girls, however this also caused traces of her and Ui's existence, as well as their memory to fade from everyone except Magical Girls, fully becoming part of the Magia Record, the Doppel System.

As Iroha, Ui and the Lil' Kyubey were now tied to the core's realm, they used the Kimochi's vast energy reserves to spread the Doppel System across the globe, with all of its inhabitants residing in the Magia Record to ensure it keeps working properly.

Iroha also used Mikoto's powers to travel back to the past and gather records of Magical Girls long gone. In the Magia Record, Touka aids with the conversion of energy as well as calculations, while Nemu aids Iroha in recording the Magical Girls of the past, as well as keeping Iroha's existence from being scattered across time.

While all traces and memories of Iroha and Ui were wiped for most people, in the Barrier of the Eternal Sakura, the Magical Girls of Kamihama can still feel their presence.

Puella Historia

While traveling through six eras of the past, Nemu created the Soul Vessel, to keep Iroha's soul safe while her body traveled through time. Touka and Nemu had also secretly planned to find a way to release Iroha, Ui and the Lil' Kyubey from the core, so they could return back to their normal lives.

Their miscalculation allowed 10^-43, whose offshoots existed in all of those eras, to latch onto her like a parasite and shut down the Doppel System once more. Iroha's very concept was scattered through the six eras she had entered, so Nemu created copies of her persona as books, and sent many of the Magical Girls of Kamihama back in time to retrieve her. Each group was given a copy of Nemu's persona as a guide, as well as a Soul Vessel to restore history and gather Iroha's concept again.

Once Infinite Iroha was restored, the Witch, 10^-43 trapped her and began her assault, until Historia Yachiyo, Infinite Iroha and the various girls from six eras, defeated her together. After her defeat, Touka and Nemu revealed their plans had led to 10^-43's usurpation, and they explained that they'd found a method to release the others from the Doppel System and restore their full existence. A few weeks later, Iroha and Ui were able to go back to their normal lives, without compromising the Doppel System, though Iroha herself still had a connection to it. Occasionally, even Touka and Nemu were also able to leave the core unattended to meet their loved ones.

On one such occasion, Mikoto guided Iroha to the Magia Record when Nemu was alone, and momentarily took over her body to create an Uwasa body for herself and an Uwasa copy of Hanna Sarasa. After the two's departure and subsequent death, Iroha had been left with Mikoto's Mirrors powers to go through time and space.

Eventually, the Doppel System began to increasingly malfunction, collecting impurities much slower and less efficiently. After Iroha and Ui found out about the issues, they decided to return to it and continue their job of maintaining the Doppel barrier. All traces and memories of the two's existence were wiped from everyone who wasn't a Magical Girl again, and Iroha, Ui and Lil' Kyubey continue to gather impurities and file records in the Magia Record, so that someday they can be conveyed to people. Touka, Nemu and Sakurako also aid them, similar to "organs" of the Magia Record, and as they compile the gathered records of Magical Girls, Touka and Nemu keep searching for a way to save all Magical Girls by using Uwasa.

Anime

In the anime, the purification process is less effective, making the Doppel take over the user more often, which is signified by her gaining a black and white smiling mask over their face. Using the Doppel repeatedly risks to it taking over completely, causing their bodies to merge significantly with the Doppel, and it causes them to act completely as Witches. This glorified, comatose, Witch-like state is known as Doppel Syndrome.

Similar to the game, Ui, Touka and Nemu make their wishes and Ui gets overwhelmed by the impurities. However, unlike the game, the details are slightly different since the purification process isn't efficient enough and Ui contracts Doppel Syndrome.

Ui's body transforms significantly and Alina buys them time by covering her with a barrier. Touka tries to take Ui's Soul Gem from her body, but she's unable to until she uses her power to transform it into another form, similar to energy. As it starts falling apart, Nemu has to place it into an empty vessel, so she places it inside the empty Lil' Kyubey herself. This makes her be excluded when everyone else forgets about Ui's existence, but she still decides to proceed with the plan to save Magical Girls and co-creates the Wings of the Magius. Like in the game, they collect the being that is now Embryo Eve and start recruiting for the Wings of the Magius, though Nemu feels regretful of her actions.

In episode 23, after the Witch Induction Device is destroyed and Touka regains her memories, her and Nemu still resolve to fuse Eve with Walpurgisnacht, which would also improve the faulty Doppel System, as well as spread it worldwide.

The premature awakening of Eve caused the system to overload, which in turn caused pain to the Magical Girls in all of Fendthope, including the ones who had already contracted Doppel Syndrome. Inexperienced girls with weak souls quickly contracted Doppel Syndrome themselves, and only the ones coordinated, like Mitama and Rena, or experienced Magical Girls, like Yachiyo, Mifuyu and Momoko, were able to bear through it.

Atop Eve, the two chase after Walpurgisnacht, which has resumed her way towards Mitakihara, while they're pursued by the Magical Girls of Kamihama.

In episode 24, it was shown that the Doppel barrier can be made momentarily visible to those with magic in events such as Eve awaking before she was prepared. It was also shown that when the barrier is in such a state, a Doppel can break through and actively make a hole in it, though it is unknown if it would have the same effect when the barrier is in an optimal state. Kuroe's Doppel was able to pierce through the barrier and then mature into a Witch by doing so. Despite the holes, the Doppel System and the rest of the barrier were left unharmed, as when Iroha fell back into it, her Doppel immediately appeared.

In episode 25, the girls of Kamihama catch up and restrain Eve against a building. However, Alina appears and lets her Doppel take over her body in Doppel Syndrome, while simultaneously taking over Eve's body, fusing them into Neo Dorothy Motherfucker. This fusion caused the Automatic Purification System's barrier to break apart, and Neo Dorothy continued giving chase to Walpurgisnacht.

Touka and Nemu use their powers to summon their Doppels one last time and chase after Neo Dorothy. Before they reach it, Ui, who is using Lil' Kyubey's body, joins them, and they detonate their Soul Gems in a suicide attack, severely hurting Neo Dorothy. After the explosion, Iroha talks to Ui's soul in a dream, where she reassures her that she'll always be with Iroha.

After she wakes up, it is revealed that the Doppel Phenomenon was transferred to solely surround Iroha, who also got Ui's Collection magic, and the Infinite form of Giovanna despite never becoming Infinite Iroha herself. With the gathered magic from the Magical Girls, Yachiyo's power, and Kuroe's Grief Seed, she turns her Doppel into a loaded weapon and kills Neo Dorothy.

Unlike the game, the Automatic Purification System in the anime does not develop, and is instead destroyed, leaving the girls in Kamihama without the Doppel Effect, and Ultimate Madoka assimilates the universe into the Law of Cycles, as a book called Magia Record.

Trivia

Based on their backup plan with the Interview Records, as well as their entries in the Puella Magi Diarium, it can be surmised that Touka and Nemu plan to use Magical Girl Records to create Uwasa bodies for the deceased girls, essentially bringing them back to life.