While the group believes the secrets are being submitted by different people, Tenji is revealed to be the author behind most of the damaging rumors. He strategically plants lies to drive a wedge between Shiho and Yutori Kokorogi , even framing others to maintain his "nice guy" facade.
The episode confirms that Tenji was the one who stole the school trip money and signed the group up for the game. His motivation is rooted in an obsessive desire to isolate Shiho Sawaragi from the rest of the group so she has no one but him to turn to.
Shiho receives a "special chance" card, which adds a new layer of risk and strategy to the game, though Tenji attempts to use this to further his own plans.