Description
Shu Itsuki originates from Yumenosaki Academy and later pursues a career as an idol and artist. Born into a wealthy, old Kansai family, he was raised primarily in a Tokyo villa. His neglectful parents led to a close relationship with his grandfather. Childhood bullying targeted interests perceived as feminine, such as sewing and dolls. Kuro Kiryu was his childhood friend, and Kuro's mother provided significant emotional support, teaching him lace knitting before her passing. This isolation fostered a control-oriented personality.

At Yumenosaki, Shu co-founded the unit Valkyrie with Nazuna Nito, serving as its leader and creative force. Valkyrie achieved prominence during the academy's "war era," but collapsed following a public exposure incident orchestrated by Eichi Tenshouin and his unit, which revealed Valkyrie's lip-synching during a performance. This humiliation caused severe trauma, earning Shu the designation of one of the "Five Eccentrics." The trauma triggered a dissociative disorder, diagnosed as OSDD-1B, manifesting in an alternate identity embodied through an antique doll named Mademoiselle. Mademoiselle represents a fragmented part of his psyche, often communicating Shu's suppressed emotions without dissociative amnesia. Shu denies practicing ventriloquism, insists Mademoiselle is a separate entity, and remains highly protective of her.

After Valkyrie's downfall, Shu's intensified perfectionism created a toxic environment, contributing to Nazuna's departure. This period involved harsh treatment of unit members, particularly Nazuna and later Mika Kagehira. Shu continued Valkyrie with Mika, though activities became infrequent. Over time, Shu underwent significant development, becoming less controlling and more open to collaboration. He acknowledges Nazuna's separate path while maintaining a complicated relationship.

Shu relocated to France for university studies, incorporating global perspectives into his art. He leads the revived Valkyrie with Mika, personally designing intricate costumes and emphasizing performances as "sublime works of art." His artistic philosophy focuses on evolving human expression and providing salvation through art. He remains meticulous and passionate, possessing a powerfully extravagant singing voice and delivering highly calculated performances.

Mika Kagehira is his devoted partner in Valkyrie, viewing Shu as a mentor and inspiration. Shu handles all costume designs and maintenance personally, refusing others' assistance. He shows protectiveness toward Mika, though their past involved strife due to Shu's earlier rigidity. His relationship with Wataru Hibiki is marked by disapproval of Wataru joining 'fine' but understanding of his motivations.

Shu exhibits distinctive traits: exceptional visual acuity, noticing minute details like 2mm hair length differences; an aversion to crowds despite being an idol; reliance on self-cooked food and croissants, though this habit is easing; and use of the term "girl" (komusume) to refer to female characters. He knits and creates clothing designs, often revisiting childhood sketches for modern adaptations.

His name carries thematic significance: "Shu" (宗) meaning "religion" or "purpose," and "Itsuki" (斎宮) referencing Shinto priestesses, aligning with his artistic mission of offering salvation. Mademoiselle's origin traces to a family storage room, gifted by his grandfather under the condition she be treated as family. She displays traits introjected from Kuro's mother, aiding Shu's emotional expression.