Izayoi

According to her in-game BlazBlue: Chronophantasma biography, Izayoi is the true form of Tsubaki Yayoi, awakened after she fully unleashed the power of the Sealed Weapon Izayoi. As stated during numerous in-game points (i.e., her pre-fight dialogue with Nu -No.13-), Izayoi is the prototype for the Murakumo Units (and, thus, the Nox Nyctores, Lux Sanctus: Murakumo). If her naming pattern matches her subsequent siblings, her official designation would most likely be μηδέν -No. 00- (pronounced mi̱dén number zero)--this would seem to be true given the 00 mark on Zero-Type Izayoi's portable and armor form and the ArcSystemWorks trailer that hinted at No. 00.

Izayoi, as a separate character from Tsubaki Yayoi, became playable in BlazBlue: Chronophantasma. She is also playable in BlazBlue: Chronophantasma Extend and BlazBlue: Centralficition.

Information
Izayoi is the true form of the Sealed Weapon Izayoi that Tsubaki undertakes to don the power of Immortal Breaker. This form was awakened twice, once during the battle with Jin Kisaragi before Amaterasu's phenomena intervention, and once after, when Noel materialized it with her power of the Eye. She is still under the influence of Imperator's Mind Eater in both occasions, but manages to break free the second time thanks to her friends. Tsubaki regains herself once more, but feels lost as she knows the Imperator's justice is a lie. However, with the support of Hakumen and Noel in her true form, she decided to fight for the justice she believes in and for the friends she cherishes. Turning away from the darkness of the past, she takes up her sword to punish all crimes and seek out the true light.

In the finale of Chronophantasma, Tsubaki joins Makoto Nanaya and Bang Shishigami in the fight against Relius Clover, Carl Clover, and Litchi Faye-Ling inside Asphyxia, a hidden dungeon below 8th Hierarchical City of Wadatsumi. They try to give Bang an opening, so he can activate the device on the Kushinada's Lynchpin, but the tag-team of Nirvana and Ignis proves to be a formidable force to reckon with. They succeed, however, as Valkenhayn R. Hellsing appears and breaks the stalemate state.

Personality
Izayoi is shown to retain Tsubaki's desire for justice, but her awakening is under a much more sinister light. She believes that the Imperator and the NOL are not to be defied, and that she is the Sword of the Imperator herself, and gives Noel, Makoto and Jin death sentences. She also refers to herself as the true light.

After Makoto, Noel, and Jin manage to free her from the Mind Eater curse, she realizes that the Imperator's justice is a lie and decides that she will fight for a justice she believes in as an individual: to fight for the people she loves and the friends she cherishes.

Appearance
Being Tsubaki's true form, Izayoi's physical appearance remains the same, with the exception of her red hair being tied into a ponytail. In addition, the appearance of her battle suit is a mix of Tsubaki's former Astral Heat and her NOL uniform, her armor being a sleeveless, black, skin-tight bodysuit with a short, slender, white outfit, and white, knee-length boots. Her pre-fight appearance lacks the robes like those of Mu -No.12- and Nu -No. 13-. Instead, her body suit has a split flare resembling a flowing dress. Being a prototype, Izayoi's armor bears a slight resemblance to the armor worn by subsequent Murakumo Units, but with two shields (which act as flight boosters and sword power-ups) floating around her instead of swords, and an overall less revealing outfit.

Powers and Abilities
Welding the Sealed Weapon Izayoi; Izayoi is an incredibly powerful being who is the sole person able to kill Observers. As well as this, her ability Immortal Breaker is capable of killing any immortal being due to the fact that the Sealed Weapon was designed to target Observers. However, one drawback to her 'Immortal Breaker' is that it is incapable of killing beings who possess the Power of Order, like Hakumen and Jin Kisaragi.

Similar to Noel Vermillion, who can fight as herself or call upon the Murakumo Unit at anytime, Tsubaki can fight as herself or summon the Izayoi at will. When fighting as Izayoi, the prototype Murakumo Unit, she is relatively weaker than her Murakumo siblings in combat (based on her battle with Noel Vermillion/Mu -No. 12-). This is especially true in her default mode where her fighting style is "primitive" compared to her siblings and her flight abilities are quite limited. However, once in her gain-art mode (Scarlet Justice), Izayoi's sword summoning, speed and flight ability (boosted by her shields) all increase--thus leveling the playing field quite a bit. In addition, her Slaver Trans-AM Distortion Drive augments her sword summoning. Finally, her hovering shields really only act as swords during her Justice Phorizer Distortion Drive by helping power the large sword thrown by Izayoi.

As with other Nox Nyctores and Legacy Weapons, there is a price to be paid for wielding the Type-Zero Izayoi. In this case (as with the Sealed Spear: Izayoi) the cost is possible blindness or "removal of the light." However, upon awaking as "the Izayoi," Tsubaki's possible blindness seems to be greatly slowed (if not avoided completely).

Etymology
The word Izayoi (十六夜) means "sixteen-day-old moon" in Japanese. In astronomy, a sixteen-day-old moon has just passed its fullest phase, so it is at this point that its brightness begins to decline. This is a reference to the Sealed Weapon Izayoi's power to induce blindess upon its wielder, namely Tsubaki.

Trivia

 * Nearly all of Izayoi's moves are references to the Gundam series, in particular Gundam 00 (Gundam Astraea, Seraphim Gundam, Trans-Am System) and Gundam Seed/Gundam Seed Destiny (Freedom Gundam, Destiny Gundam, Justice Gundam, Strike Gundam, Aegis Gundam, Strike Noir Gundam, Gundam Astray Mirage Frame).
 * Her eyes are red, but in Chronophantama player lobbies, her pixel model's eyes are blue. Even though Tsubaki was freed from Mind Eater, in the story mode, her eyes are still red as Izayoi.