Being Noel’s true form, Mu’s physical appearance remains the same, with the exception of her eyes having changed to a soulless blue featuring tiny pupils (in some artwork, her eyes are completely blank in a bright blue that is “glowing”), and her long blond hair with a distinct fray. Outside of combat, her outfit is similar to Nu-13’s, but with a more elaborate and advanced design, featuring lights, thigh-high toeless socks, and blue nail polish on her hands and feet. She wears an armored headplate featuring long horns like Hakumen’s. When in battle, she dons armor similar to Nu and Lambda-11 with the same general design and floating blades. However, unlike the former two, her armor shows off much of her skin, retaining little of Noel’s Control Organization outfit, which seems to have disintegrated. It also features large magic power regulator pauldrons.
As a child, she was wearing a blue experimental robe. Her hair retains the distinct fray. This version is also seen when Mu is affected by Amane’s Astral Heat.
In BlazBlue: Chronophantasma, as Noel is now in full control of her powers, Mu no longer has blank and lifeless pupils, her blue eyes are no longer dulled, and now have definition. This is carried on in BlazBlue: Centralfiction even after Mu splits from Noel; she still has defined eyes.
While Noel Vermillion is the definition of a “shrinking violet”, Mu-12 is completely the opposite: she becomes emotionless, and wants the world to be destroyed. She only acts based on Terumi’s orders, and she believes that the world “hates her”, and is filled with nothing but lies. When she believes the world hates her, she feels more anguish in her speech than when she’s emotionless, often switching between ranting about the world hating her and her usual, robotic speech.
However, after Noel gained control over her powers and transformation into Mu, she now retains her normal personality and emotions when in Mu’s form. Upon transforming willingly, Noel noticeably becomes more “in control” of her emotions, as opposed to when she felt as though she blacked out when fighting using Bolverk. As a result, she is more calmer as Mu instead of Noel, as shown in some of her victory quotes in Chronphantasma; Noel will still scream at the sight of Arakune’s bugs, but as Mu, she questions about Arakune’s existence.
Despite being more outspoken, Noel is still apologetic even as Mu, as shown when she fought against Tsubaki in her Izayoi form when she awkwardly ask her to return as she apologize for taking her place in the timeline they are in.
She is also shown to be more confident and outspoken, though she still has some degree of shyness and embarrassment regarding her rather revealing attire, particularly when facing Ragna, especially facing Kagura and trying to explain her attire to Mai in Centralfiction and Makoto in Chronophantasma.
Mu was made in the 5th Hierarchical City of Ibukido. As the twelfth Murakumo Unit to be made; she was christened as Mu-12. Made by the 7th Agency to become the heart for the Black Beast and to fuse with Hazama, the body, she was to be made in the middle of the Ikaruga Civil War to become the ultimate weapon for the 7th Agency to use against the Control Organization. However, this plan was thwarted by Takamagahara as they fired Highlander: Takemikazuchi upon the city, utterly obliterating every living being within the blast radius. Mu, in the stage of being smelted, and thus, in a cocoon, was saved from the same fate as the others, but left without an identity. She was later found and then subsequently adopted by Edgar and Claire Vermillion and christened as Noel Vermillion.
BlazBlue: Continuum Shift
Moments after Mu was awakened, Yūki Terumi gave her the order to destroy the Master Unit, Amaterasu. She goes to the open Gate, where she fights Hakumen and Jin Kisaragi, defeating Jin. When Ragna the Bloodedge arrived, he finally defeats the Godslayer by awakening Noel’s mind, but sacrifices his left arm in the process.
Thanks to Rachel Alucard, Noel regains Mu’s powers and abilities in order to save Tsubaki Yayoi with the power of the Blue. She no longer possesses the same cold, destructive personality she had after her initial awakening, retaining Noel’s personality and memories instead.
After seeing the Gate of the Blue inside of the Black Beast, Noel separated Mu from herself. This separated Mu had Noel’s personality and memories, and these memories were unaffected by Embryo. She would be discovered by Ragna, who then requests for him to bring Noel to her so they could become whole again. However, when Noel sees Mu, she panics and loses consciousness. It was then revealed that Noel had split off from Mu from the trauma of seeing the Gate. Too frightened by her power, she discarded Mu in an attempt to bury the memories in her head. During Act 1, Mu was transported to an alternate world where she had become the most hated enemy of the world, but has no recollection of the crimes she was accused of. Of her first casualties was Rachel, the very same person who had helped her to manifest and wield her power. In Act II, she was told to have claimed the lives of innocents and that she had killed both Ragna and Jin, the revelation causing her to go mad with grief over her actions.
When Ragna, Jin and Noel are teleported to the church where they originally lived, Ragna took Noel to a passage leading to an underground area right below the church; where the Black Beast’s husk originally laid. It was there that Noel and Mu met yet again. This time, Noel accepted Mu as part of herself and the two became whole again. In the final battle against Izanami, Noel transformed into Mu in an attempt to absorb Izanami into herself as it was the only way to neutralize her as she cannot truly die. However, Izanami tries this ploy against her by attempting to consume her. However, while she was preoccupied with Mu restraining her, Ragna stepped in and used his Blue Grimoire to stop Izanami, giving Mu ample time for her to complete the assimilation.
After Terumi was at last slain, Ragna carried Noel to the Master Unit, wherein the Origin’s body lay for her to become Saya.
Powers and abilities
As with her sister units, Mu is a very deadly opponent on the battlefield. As the Kusanagi, the Godslayer, she was designed for the sole purpose of destroying the Amaterasu Unit. When fusing with the true Blue, she dons an advanced version of the armor worn by Nu and Lambda. Like them, she has the ability to hover and fly through the air, and can use the disembodied swords behind her to attack and defend herself. She is also able to conjure up an energy barrier by forming the blades into a rhombus-like formation. Mu possesses spatial related powers, preemptively striking opponents by opening wormholes and stabbing her weapons through to the other side and attack them at a distance. In both her Astral Heat, God Slaying Sword (カミゴロシノツルギ Kamigoroshi no Tsurugi, localized as Sword of the Godslayer) and in BlazBlue: Alter Memory, Mu is capable of summoning gigantic swords that she can fire at her opponents and is even capable of defending with them.
Mu’s Drive is Steins Gunner (シュタインズガンナー Shutainzu Gannā), which involves Mu displacing floating units across the battlefield. These units come in three types depending on the number of blocks, which open up several offensive options, mostly in attacking the opponent from all angles and even reflecting off of each other in order to disorient the opponent’s focus. These units will fire a beam of energy when initially deployed, but Mu can fire her own beams into these units to maximize their potency, tracing its trajectory from one unit to the next until it reaches the last unit wherein it immediately tracks the opponent. Originally, she could simply detonate the units at will if desired with Feathery Slash of Heaven (アメノハバキリ Ame no Habakiri, localized as Divine Wrath of the Heavens), but this move was replaced in BlazBlue: Centralfiction by Endless Rise of Earth (クニノトコタチ Kuni no Tokotachi, localized as Tokotachi Blade), where the units instead converge on the opponent and ram into them. Her Overdrive, Steins Geyser (シュタインズゲイザー Shutainzu Geizā), shortens the time in which the units fire off a shot and her Exceed Accel, Earth Thunder (ツチイカヅチ Tsuchi Ikazuchi, localized as Pillar of Light) has her swords spin around the opponent before bursting into several pillars of energy that consume them.
- Mu’s name comes from “μ” (mu), the twelfth letter in the Greek Alphabet and serves as the beginning bit of her Murakumo Unit serial number. “12” serves as the final part of her serial number and is used to show that she is the twelfth Murakumo Unit.
- Most of Mu’s moves – save for Steins Gunner, Steins Geyser, and God Slaying Sword – are named after various deities and weapons from Shintō:
- Yata no Kagami – one of the three Imperial Regalia of Japan, it and the Yasakani no Magatama were used to lure Amaterasu from a cave.
- Totsuka no Tsurugi – the sword of the god Susanoo, and the sword Izanagi used to slay his offspring, Kagutsuchi.
- Ame no Habakiri – another name of the Totsuka no Tsurugi.
- Ama no Habaya – arrows of the bow Ame no Kagoyumi.
- Tsunugui – the deity Tsunugui no Kami.
- Furu no Tsurugi – sword of the Takemikazuchi no Kami.
- Omohikane – Omoikane no Kami.
- Ikutachi – a sword capable of bringing the dead back to life.
- Tsuchi Ikaduchi – one of the eight thunder gods.
- Kuni no Tokotachi – the first kami.
- When taunting, one can see Mu-12’s headgear fall down and cover her face. This is exactly like Noel’s taunt.
- Mu-12 is the only playable character pre BlazBlue: Chronophantasma who does not have their own story mode, even after BlazBlue: Continuum Shift Extend was released.
- Mu is the only character who features another playable character in her pre-fight sequence, usually whoever is her “superior” at the time. (Terumi in BlazBlue: Continuum Shift and Rachel in BlazBlue: Chronophantasma).
- Mu is one of the few characters with alternate playable forms. Mu-12 is the true form of Noel Vermillion.