Maybe she was watching over him and just wanted him to actually leave the good for nothing party but knew that wouldn't happen from his own will since he still seems to want to join it
she's been tasked to watch over him by kuruto's master.. its stated on earlier chapters... and she didnt participate she just "watched"
Watching while he literally got kicked is participation in itself. She was even laughing
she cant do anything about it since he's the one who chose to join and stay on that group and besides their goal is for him not to stand out and his ability not be discovered since its a big deal if it is known..
It said that she is the “great sages” disciple and I assume that the great sage is Kuruto
the great sage is not the girl but kuruto's master..
It depends on what her task was. Just watching over him making sure he doesn't stand out or die. It helping him with life? Having him voluntarily leave the party without actively telling him to do so,there can be several scenarios. Unless we know more of the story we can't say anything with certainty
what's with the black-haired ex party member? She participated in humiliating him when he was kicked out of the party and it seems like she knows he is god level OP