Board Thread:Questions and Answers/@comment-200.246.78.2-20160414222954/@comment-8695373-20160415110733

What is known, is that right now Noel is Amaterasu. It's most likely that Amaterasu dumped "our" Noel in Mu, and took her Noel body to herself only in CF. Amane's arcade hints at this: Rachel said that if they sent the empty Master Unit through Nemesis Horizon back to wherever it came from, their world will die. That means that when the Unit was on the other side of the Nemesis Horizon, it was not "empty", something was there, and this something escaped sometime after the Unit was summoned.