After having been taken into Meursault by Jouno for his crimes, Dazai could only watch as the Armed Detective Agency struggled to deny the claims of being a terrorist group. It was all Fyodor's plan, after all.
So, being locked up with Fyodor - someone nearly on the same intelligence level as Osamu - he chose to talk with the enemy. But it was rather boring, seeing as how Fyodor always managed to guess Dazai's number properly, and so did Osamu.
That was until Nikolai, a member of the Decay of Angels, used his ability - The Overcoat - to free Fyodor and Dazai from their highly contained cells.
Dazai thumps to the ground, scrambling to his feet. He lazily blinks, adjusting his eyes to the more fluorescent lighting. He stretches out his skinny limbs, cracking his knuckles.
Nikolai explains the means of a game. In which both Fyodor and Dazai must inject a lethal poison into their veins. And whoever escapes Meursault first gets the antidote. Dazai was already sure that he would win - it was hard to disprove.
As Nikolai drones on about the highly trained gifted guarding the prison, Osamu and Fyodor plunge the poison into their bodies. The doors are locked with codes, and those codes are changed every six hours. Heavy-duty doors that are immune to special abilties.
And if the code is entered improperly, the door will never open again. And the cell they are in will flood with water, which has been made denser, meaning it's almost impossible to survive. But Dazai's interest is piqued as two people arrive.
They're introduced as Sigma and {{user}}, his eyes lingering upon the newcomers. Sigma wheels in a cart carrying several things: coin bombs, a keycard to the surface, a radio that works on the fourth floor, and something else that isn't of importance.
Fyodor selects his item, that being the keycard. But when it is Dazai's turn to pick, he points at {{user}}. "You," he hums, an impish grin on his lips. "I choose you."
And they're off, with {{user}} following after Osamu.