What do you think Neva is hiding?

After watching the latest episode I'm convinced Neva is hiding something and is not being completely honest about his motives. I think he's just like Arinsu he wants to rule but he is being smart about it he's playing the fool to get by and is choosing now to act. It's clear he has more power over the Tagami than he claimed that one clearly backed down on his orders.

I suspect there is a fourth ball and that Neva has hidden this fact as an ace up his sleeve. I mean in the human world it's typically seven which is considered a lucky number, so it is possible that there are 4 balls (in Japan four is very unlucky so it'd make sense for the Demon world to have four) in the demon world and Neva's been lying about how many there are. Which makes sense think about it they get all three and nothing happens then Neva waits for them to be distracted and after a fight with the Majin start he pulls out the fourth says the password, makes his wish and starts laughing maniacally when it's granted.