Given that Mana has already 10 years left in her life span. I guess the black-suit people are under Kotori's order to retrieve her before DEM Comp. could.
She has no ill intent towards her but Mana is Shidous' real sister and she is also worried about her body. Now that she knows the gist of things about her absurd strength and DEM's vile secret.
What is left for her to do is to help her brother and uncover the secret of his identity if he is human or Spirit?
