Board Thread:BlazBlue: Centralfiction/@comment-8695373-20161004174202/@comment-8695373-20161004202408

It was said that Susano'o is bound to Amaterasu, which lets her order its wielder, but I don't think anything like this was said about Tsukuyomi. And Rachel is already on Amaterasu's side, so it doesn't matter anyway.

If something will happen to Amaterasu, it will not affect Rachel via Tsukuyomi. Terumi wants to kill Amaterasu and then use Susano'o Unit, so nothing will order him around. Killing Amaterasu will not affect other Units' wielders.

The Arcade Mode's events will be shown for at least 7 episodes of Story Mode, and Hakumen wasn't killed in Arcade, so I think Susanoo will appear somewhere near the end.