Seseri Chōno, 28, is the Deputy Senior at the Butterfly Law Office, partnering professionally with his older sister and Senior Partner, Ageha Chōno. He possesses distinctive blue hair that curls outward before turning inward and amber eyes. His magical ability, "Seseri Stylish," allows him to construct human-sized robots from nearby materials, its effectiveness dictated by resource availability.

He maintains a stern and disciplined demeanor, especially within the office. This strictness manifests prominently in his dealings with junior colleagues like Cecil Sudo; he frequently reprimands her for perceived irresponsibility or procedural missteps, even docking her pay for violations such as traffic tickets. His no-nonsense approach positions him as the primary enforcer of order, contrasting sharply with the unconventional methods of other team members, whom he privately dismisses as "The Pirates Who Don't Do Anything" due to their investigative antics.

As Ageha's younger brother, Seseri defers to her leadership while collaborating closely with her. Their familial bond underpins their working relationship, yet his rigorously strict personality remains consistent regardless of personal ties. He works regularly alongside colleagues Koromo Sasori, Mitsuhisa Hachiya, and Cecil Sudo on cases concerning magical law.

His role focuses exclusively on legal advocacy within the specialized "magic courtroom" system. He adheres strictly to procedural norms and magical regulations, demonstrating steadfast commitment to the firm's operations despite occasional friction with its more eccentric members.