Izanami

Hades: Izanami, formerly the Imperator of the Novus Orbis Librarium, is the Drive of The Origin and the embodiment of death. She is the former wielder of the Nox Nyctores - Gigant: Take-Mikazuchi and possessed the body of Saya. Her goal was to bring about Doomsday but she was defeated through the combined efforts of Mu-12 and Ragna the Bloodedge, and is now one part of Noel Vermillion's soul.

Izanami first appeared at the climax of BlazBlue: Continuum Shift and became playable in BlazBlue: Central Fiction as the final boss of Arcade's Act II.

Central Fiction
Before the Doomsday began, Izanami went to the Amaterasu Unit, and opened it up, showing that inside, there was no one. She soon summoned Noel and Rachel to her location to force Noel to Observe where she had placed Ragna – inside the Embryo. She then journeyed into the Embryo herself.

Inside, she bathed in one of the Prime Field coffins, asking Relius about the vessel she was possessing. She dressed herself and travelled to Ikaruga, realising that Nine had set the chosen against her, and later watched as Relius and Ragna fought in Akitsu, being interrupted by Azrael and fighting him. He grew bored however since there is no life emanating from her, and the two formed a pact – should Azrael defeat all the chosen, Izanami would grant him access to the world of the Gods where he could fight them for all eternity.

Witnessing Azrael fighting against Ragna, she summoned the latter to her location next to the Amaterasu Unit. They fought, every moment with her mocking him with Saya’s voice. Noticing that his strikes were filled with unwillingness to hurt his sister’s body, Izanami rammed herself into his sword, telling him that she cannot die as Amaterasu’s Drive. Amaterasu intervened and used phenomenon intervention to send Ragna away from her location.

Izanami infiltrated Nine’s workshop, finding her defeated by Ragna. She offered death to Kokonoe, Celica, Jubei, Ragna, Jin, Nine, and Rachel before being stopped by one of Nine’s strongest fields. Nu followed after her master, attacking the witch but being stopped by Jubei. Izanami remained inside the workshop as time froze over, watching Nine die. She broke the space-time, transferring the Requiem to a different location and issuing an illusionary message to Ragna, Noel, Kagura, Jin, Hakumen, Tsubaki, and Ex Machina: Minerva, warning them all that if they could not find her in three hours, they would all perish in Requiem’s explosion. Eventually, Ragna and Mu found her, and she was absorbed by the latter despite being up a resilient fight. Izanami, from that point on, no longer existed, having merged together with Noel’s soul.

Imperator
''Officially, the Imperator Librarius. She's the highest ranking official in the Novus Orbis Librarium's pyramid. She is, however, the same person as Ragna and Jin's younger sister, Saya.''

''It would not be an exaggeration to that the entire NOL exists to serve her agenda. Directly below her command is a group of 12 families, known as the Duodecim, whose strength is immense and unknown.''

''In the episode of Continuum Shift, she successfully awakens the Takamagahara with Hazama and Relius' help. She now has her sights set on the Master Unit's destruction.''

Hades: Izanami
''The former Imperator, highest ranking political official and commander of the Novus Orbis Librarium. She is the ruler of death. Her goal, to bring upon the day of reckoning, and return the world to nothing.''

''Her vessel is Ragna and Jin's younger sister, Saya. Occasionally, Saya's personality will surface.''

However, it is still unclear whetehr that is because the blend was over or underdone.