That final scene is super-crazy. I mean, is this all an illusion by Shino?
I think, rather, that this is some 4D-chess Deido is playing to make Kurenai credible. If Kurenai attacks them to protect him, they'll think she's been controlled by the invaders/Deido. So Deido's attacking her so they'll believe she is not possessed… and thus won't attack her, and might believe what she has to say. Shino's lot maybe have fallen for it in the hope this will get Deido killed for sure (for attacking Kurenai) and added the girl to give them less time to think.
Now, I wonder what Deido is on about, telling Kurenai that it's only a "theory" his death will open up the paintings? He was the one who told her that!