Ataru Chuuou, a colleague of Ryuuou Edogawa, operates alongside Julia Katsushika within the series. His trajectory shifts when Julia’s actions enable Ryuuou to enslave him via the SCM system, forcibly integrating him into Ryuuou’s faction. This enslavement erodes his autonomy, transforming him from an independent actor into a subordinate governed by the SCM’s constraints.

In exchanges with figures like Adachi, Ataru displays a weary acquiescence to his enslavement, acknowledging past considerations of escape while settling into passive compliance. His pragmatism surfaces in cautionary advice to others, stressing the blurred ethical lines within SCM conflicts and the imperative of skepticism in a landscape where allegiances and intentions shift unpredictably.

As part of Ryuuou’s group, Ataru engages in tactical planning, including speculation on the SCM’s limitations—such as potential loopholes or partial resistance to its control. His analytical contributions fuel debates on the system’s mechanics, subtly underscoring its intricate design. While his insights illuminate facets of the SCM, his personal history and motivations beyond his subjugation remain undefined.