They lure Third to the roof of the building, and when he draws his phone to check where they are, Amano punctures it with a thrown dart, killing him.
Deus brings the eleven remaining competitors into a vision and explains the rules: They must discover and kill each other.
He names Amanao, First. No doubt the top contender if he could pull off a miracle like that.
It was actually Gasai's doing, but Amano has the target on his head.
Don't worry, Gasai will protect him, with all the force that a Yandere girlfriend can muster. (Worry.)