Ataru Chūō operates as a colleague within Ryuuou Edogawa's organized group, actively participating in strategic operations involving Slave Control Method (SCM) devices. Under Ryuuou's directive, he recruits Taiju Nakano into their faction following Nakano's involvement in an altercation where Zenichi Bunkyō assaulted Shiori Adachi.

Ataru directly confronts Zenichi Bunkyō after this attack. Witnessing Zenichi subdued by the SCM-equipped dog Zushioumaru, Ataru intervenes and offers Zenichi a position in their group. When Zenichi refuses, Nakano steps in to duel him on the group's behalf.

He engages in SCM duels to further Ryuuou's objectives. Ataru is implicated in a manipulative scheme where a child, acting under apparent coordination with his faction, lures Zero Shinagawa into an SCM challenge. The child presents a false story about avenging his father to gain Zero's cooperation. During the quiz duel, the child answers for Zero, causing Zero's loss and enslavement.

Ataru demonstrates awareness of other SCM users and assets, attempting to claim the dog Zushioumaru upon recognizing its SCM after the dog intervened against Zenichi. Zushioumaru returns to its owner, Eia Arakawa, thwarting Ataru's effort. His background, origins, and character development beyond these events involving Ryuuou's SCM conflicts remain undocumented.