The master brain could be Josy. This little horny bitch.
On the screenshot 1 you should look at the eyes of Josy. She has always watched the MC out of the corner of her eye.
Lily has something in her right ear and I don't mean earrings (screenshot 2). Don't start now so that this is the sky visible through a gap. To the right of the black is still some head.
But a picture in front of it with Mona makes it interesting (screenshot 3). DPC also leaves clues on the skin. I conjured a red circle around it. What do you think it will be? I was really surprised when I saw that. At the end of EP4 DPC left a hint on Mona that she will leave at the end of EP6. The screenshot 4 is slightly edited so you can see it better. I just removed the color and played a bit with the exposure and black level. To the right of what looks like a person on a surface, you can see a woman with 2 suitcases.
Did Josy maybe start the fight for the MC already at the end of EP4? Mona mentions at the party that she would also like to fuck with the MC and Becky was standing next to her when she said that.