Much younger sister. She is 25. Sometimes when we're arguing she would ran amok, screaming and destroying furniture near her to justifying her righteousness. She even smash my phone and tilt down our mom's closet once.

When she finally realize she is wrong though, she would keep quiet if not she would look up our past mistakes and makes it as an issue again. She never apologizes one. She is salah, but us other siblings are the ones have to apologize.

And any personal issues among siblings and family she will direct to family's group Whatsapp, not through personal Whatsapp.

Her attitude is just like that single old aunty manager / boss at office. Nightmare to everyone.

She is not mentally ill. Just pure narcissist.

Btw as a person she is actually ok, caring and friendly. Just don't make any issue with her, even small ones.