... and they've been hypnotised by Twelfth. Information about the future is worthless if it's false.
Gasai figures it out, but also believes Sixth is poisoning Amano against her.
She give him an ultimatum: come with me and live, or stay with Sixth and die.
Obviously, because the bad guys are after Sixth. This isn't her threat.
Twelfth, Hirasaka Yomotsu, is insane. He thinks he is a super hero.
Gasai dispatches him.
But it's a double cross! With Twelfth gone, the cult is un-hypnotised, and Sixth turns on them.