@RedMarks Jinta was adopted into the Shima family, so no, she's not.
Honestly, I don't understand how she can be so irrational. In the first series she was very calculating and got what she wanted through clever emotional manipulation. But with Jinta she's like all texas chainsaw massacre on him and expects him to just go along with it, which he doesn't really respond to beyond general fear and has literally already stabbed her one time as a result. The kid stabbed her once for her craziness; is she really sure he isn't gonna do it again?
Is she actually insane now, instead of just a psychopath?