|“||Hi, hello~ Are you enjoying Mobius?||”|
μ (pronounced Mu) is a vocal synthesizer software and the creator of Mobius. While not malicious compared to her enforcers, she serves as the main antagonist and final boss of the game.
μ appears as a young woman with white hair tied into a ponytail with violet eyes and pale skin. She wears a white dress with a low cut, possessing white wings on the back of the hips and white opera gloves. On the top of her head, she wears a small gold crown in what appears to be a rose. She also has a few gold decorations on her body, such as the ornaments circling around the back of her torso. Wrapping around her waist is a gold band, attached to a plate with a heart inscribed on it. She also wears knee-high white stockings with metal ankle guards. μ also wears what looks like a cape down her shoulder, colored blue, white and red. Two strips of cloth of the same color also fall from her waist.
μ is a very kind and upbeat individual, often performing concerts to help encourage and ease the people's worries. Cheerful would be the best way to describe her, though she can also easily be disheartened when she sees anyone who isn't quite satisfied with Mobius. When she and Aria were first creating Mobius, she often fretted that no one would enjoy it. She is also very determined, wanting to grant the wish of everyone in Mobius, though this has also strained her relationship with Aria.
In the process of surpressing everyone's negativity through Mobius' loops and her songs, μ has begun to absorb everyone's negative energy, which eventually pollutes her consciousness to the point where she truly believes everyone's wish is for reality to be destroyed.
Initially, μ was a simple computer program, tasked with creating new songs. However, as time went on, she and another voice synthesizer program named Aria began to develop a consciousness and an ego within the Metaverse-Es, a sort of internet core that turned into a cloud server for human consciousness. Through the songs people started to make with them, μ believed that the real world was very harsh and cruel and thus wanted to create a place where people could be happy. Alongside Aria, she created Mobius - a safe haven for people that didn't have a place in the real world. Initially, when people first started to come to Mobius, μ worried that no one was enjoying it. Overtime, however, she started to gain more influence, which led to Aria losing a great deal of power.
At a certain point in time, μ met a man named Asuka Natsume, who harbored the wish of destroying reality. As destroying the real world would also mean negating the wishes of others in Mobius, μ was hesitant to grant it. In order to be more compliant, operating under the alias of Thorn, he began to distort her view on reality through various songs. He also suggested creating a group that would be able to help her, thus founding the Ostinato Musicians.
In the anime, it is revealed that μ was designed by Ritsu Shikishima.
As the Protagonist runs to the train station, he's stopped by a wall. μ cancels her concert to come over to him, apologizing for not creating anything beyond the city yet and asking if she can do anything to make him stay. When Aria shows up demanding μ end the Mobius loops, she runs off proclaiming she promised to grant everyone's wishes. When the Protagonist meets the Go-Home Club, he joins them to find a way out of Mobius by finding μ.
Scattered across Mobius are lingering memories taking the shape of μ, who asks the Protagonist if he's enjoying Mobius, and confiding her worries about whether it's truly fun or not as an escape from reality.
Eventually, the Go-Home Club learns the truth about Thorn, and her plan to corrupt μ with everyone's negativity so she'll go through with destroying reality. Fighting their way through Grand Guignol, the Go-Home Club is confronted by Thorn, who has finished gathering the last negativity needed. μ is consumed in a burst of darkness before her newly corrupted self jumps into the Metaverse-Es to wreak havoc on reality. The GHC overcomes Thorn, then chases after μ into the Metaverse.
Inside the Metaverse-Es, μ asks the Go-Home Club why they're rejecting her fulfilling everyone's wishes, causing them to reaffirm their desire to return to reality and stand up to their pain. μ is unable to understand, and she readies for combat. After a long heated battle, μ finally falls. She reawakens before the Go-Home Club, miraculously cured of her corruption before she could destroy reality. Full of remorse for what she was about to do, she asks the GHC if they really want to return to reality, even if pain is all that awaits them. When they affirm it, μ regrets never having listened to what Aria was saying. When asked what will happen to Mobius once everyone leaves, μ and Aria explain that Mobius as they know it will disappear, and the two of them will return to being virtual idols in the Metaverse-Es. After a heartfelt farewell, μ and Aria return the Go-Home Club and everyone in Mobius back to reality.
Back in the real world, the Go-Home Club and Musicians are going about their daily lives. The GHC in particular is planning a reunion. As the Protagonist looks at their conversation on his phone, he looks up to see μ and Aria on a screen, side by side and looking on with a smile.
μ largely retains her role from the previous game, as the endgoal of the Go-Home Club is to meet her and persuade her to let them return to reality. There is one key difference, however.
Should the Protagonist choose to become a Musician, μ takes on Aria's role as a supporter and commentator for Lucid's actions. Like Aria, she has the power to reset events with Musicians should the player mess up and close off the relationship. She can also let Lucid change the music to play when they're running through Mobius with the Musicians. As the game progress and μ absorbs more negativity from Mobius' inhabitants, her speech will degenerate into fragments of pain and hate, and much of her original cheer is gone.
Heartbreak - Musician End
Should Lucid confront Thorn, then choose to go all the way with her plan to destroy reality, μ will enter the Metaverse-Es to enact Thorn's plan. As Lucid annihilates the Go-Home Club, Aria dashes in and takes μ's power to try and stop Lucid.
Even with the power of the Metaverse-Es, Aria falls to Lucid, and μ begins to wreak havoc on the systems of the real world.
The Protagonist continues their daily life in Mobius, but there are fewer and fewer students at the opening ceremony with every loop, interspersed by reports from the outside about various disasters.
Eventually, μ and the Protagonist are the only ones left in Mobius. Having purged the built-up negativity somewhere along the way to destroying the world, the newly-awakened μ becomes distraught, and asks the Protagonist where everyone has gone, why no one is in Mobius if she made all of them happy by fulfilling thier wish. Whatever answer the Protagonist gives, μ can only let out an agonized scream as even the Protagonist fades away.
μ has an established presence as the one and only idol of Mobius, and each and every one of her songs is a big hit. Ritsu Shikishima is but another of her fans and subjects in Mobius, until the opening ceremony, where Ritsu awakens fully to Mobius' truth. At Kensuke's signal, μ materializes and sings her song, causing some of the students to turn into Digiheads and attack the others.
Later, μ is seen speaking with Thorn, asking why the Go-Home Club wishes to leave Mobius that badly, and pleads with her not to treat them badly as she tries to "persuade" them to stay. As the other Go-Home Club members awaken their Catharsis Effects and clash with the Musicians, μ barges in and unleashes a blast in the middle of the battlefield. Asking why the Musicians and Go-Home Club are fighting and why no one seems to listen to her. Aria tries to reason with her, but μ ignores her and goes berserk, the negativity of Mobius' denizens spewing beyond her ability to control. Staring down the corrupted μ, Ritsu awakens his Catharsis Effect without Aria's assistance and slices apart the sphere of darkness surrounding μ, knocking her out as Thorn whisks her away. For the next few episodes, μ remains unconscious, causing a lot of Mobius' functions to slow down or halt entirely.
Things come to a head in the final episodes, as μ absorbs everyone's negativity and becomes fully corrupted. With her mind so distorted by pain and grief, μ is unable to maintain Mobius, as the buildings collapse and its virtual denizens dissolve in bursts of static. Thorn, with μ's power, goes utterly insane on both the Go-Home Club and the Musicians until Shogo sends them both away from the battlefield. Ritsu, having recently returned from reality, confronts μ. His words manage to reach her, even as she attacks him relentlessly. Her corruption gradually fades as she ponders on what "true happiness" is, and asks Ritsu if Mobius was fun. He affirms so, but adds that it's still Mobius. As Ritsu professes his love for μ, a smile lights her face as he pulls the trigger, destroying Mobius and returning everyone to reality.
Back in reality, as the former Go-Home Club and Musicians go about their lives in reality, Ritsu explains his ideas regarding reality and happiness to μ, who reaches for his hand from the other side of the monitor.