Amaterasu, also known as the Master Unit(CP Opening, Terumi says ___________. Near the end of the CP Story Mode, Relius explains the Master Unit to those present. He calls it The Master Unit, Amaterasu), is one of the handful of manmade gods in the Blazblue Universe. (mechanical appearance) As of present, it is not clear who made it, however. It is considered to be female. (On CP Story Mode, once they see it, most of the cast starts referring to it as a "she". Rachel's story being about it, she specified that the writer of that same book was a girl.)
Normally it is completely out of contact the the Blazblue World(Almost no one has seen it, and _____ thought it was incredible that Relius and Shorichiro almost made contact with it the day the Black Beast was made, CP Six Heroes Story Mode), and exists somewhere above it.(It comes down from the sky when finally summoned at the end of the CP Story Mode)
It is thanks to the Amaterasu, on a fundamental level, that the Blazblue world is able to save itself from total annihalation and repeat it's time cycles(link) over-and-over again.(Relius explaining that Master Unit thing, again. Rachel explaining that book thing, and Ragna acknowledging that this was what she was referring to. Without it, the Blazblue world as it's seen today would not exist._____ says at the very end of the CP Story Mode that "without [the Master Unit], the world as we know it, or something, will stop existing!)
Terumi has encountered it before (CP Opening, him saying that "what nightmares await me this time?! thing).
Relius has been wanting to destroy it for quite some time.(End of CP Story Mode, when talking to Bang and Kokonoe, where he explains that Black Beast thing, and Amaterasu's memories thing). He was attempting to make contact with it in an experiment with Shorichiro(link), which ultimately led to the summoning of the Black Beast(link) instead. (_____ thought it was incredible that Relius and Shorichiro almost made contact with it the day the Black Beast was made, and Jubei gets upset and says they were trying to produce work far beyond their time, saying that it backfired, and summoned the Black Beast -- CP Six Heroes Story Mode.)
Izanami(link), another 'god', had her sights set on fusing it with the Nox Nyctores weapon Gigant:Take-Mikazuchi(link), to create a new Azure(link) (which is another manmade god on Blazblue.) (CP Story Mode End, when she describes this to Rachel) However, Rachel Alucard(link) saved the Amaterasu by protecting using her own mighty Nox Nyctores weapon, the _______(link), protecting the Amaterasu in an impenatrable force-field known as an Absolute Barrier(link).(CP Story Mode, when Rachel calls upon the _______. And She says that Noel won't be able to reach the Master Unit right now, because ________ has surrounded it with an Absolute Barrier).