Agnes Boulange is a traveling puppeteer performing circus acts with automata puppets in the fictional city of Ert'Aria, frequently staging shows before a cathedral reminiscent of Notre Dame de Paris. This evokes the cultural archetype of street performers in such historic settings. Her distinctive talking cat puppet, Tango, participates actively in performances, serves as her private confidant, and occasionally collects money from audiences.

As daughter and apprentice to the skilled puppeteer Mise Altoise—creator of the automaton Minette—Agnes journeys across the world driven by a core personal quest: to locate her missing mother, who is also her mentor. This search fundamentally shapes her character journey.

Agnes exhibits a notably large appetite, particularly for desserts, a recurring trait in her narrative. Her storylines intertwine with Clan Oasis, an adventurer’s guild, where she collaborates with members like Leicester Maycraft to unravel mysteries such as Minette’s origins. Over time, she develops romantic feelings for Leicester, contributing to the series’ harem dynamic alongside other female characters.

She maintains friendly relations with most Clan Oasis members, though her closeness to Leicester occasionally draws jealousy from figures like Carina Verritti. Her automata, especially Tango, offer emotional support during quests and personal uncertainties. Physically, Agnes possesses pink eyes and orange hair—sometimes noted with pink undertones—styled in pigtails, often accessorized with a performance hat.

Her development centers on balancing her artistic career with the search for familial bonds, gradually integrating into Clan Oasis’ communal activities while navigating emerging romantic emotions within the group’s dynamics.