Seven of Diamonds ('cuz I don't think that they'd understand)

Eventually the two last players walk in, two young men, each carrying a big gun. If this is a diamonds game like Chishiya suspects, that's not going to be very useful for them.

The one with an eyebrow piercing walks onto the stage first, confidently, unbothered to be walking into a death game. The man behind him seems as anxious as the other players, fiddling with his gun to calm himself. As soon as he steps onto the stage, the announcement voice blares out of the speakers at the corners of the auditorium.

"Registration complete. Difficulty level, seven of diamonds. Game, mathletics." Chishiya is glad this is a diamonds game, and strangely, the pierced gunman seems to be glad about it too, a wicked smile on his lips.

~Or, before Chishiya joins the Beach, Chishiya and Niragi meet at a Diamonds game~