Wien Margarete begins her story as a third-year junior high student before enrolling as a first-year at Yuigaoka Girls’ High School. Hailing from Austria, she speaks Japanese and English fluently, excelling in foreign languages. Her full name nods to Vienna, her homeland’s capital, though her surname traditionally would precede her given name in Austrian custom.

Initially a fiercely independent school idol, she balances reserved poise with blunt competitiveness. Her fixation on outperforming Kanon Shibuya arises from a need to validate her skills after rejection from a prestigious Austrian music school, a setback that compels her family to tie her Japanese enrollment to winning the Love Live! competition. Openly critical of school idol culture, she paradoxically embraces it as a means to her goal, debuting solo with "Butterfly Wing," a song accentuated by a ballet-infused music video reflecting her classical training.

Her trajectory shifts upon joining KALEIDOSCORE, a Liella! sub-unit, and later transferring to Yuigaoka to fully integrate into Liella! itself. This follows her defiance of her family’s proposal to recruit Kanon for training in Austria, choosing instead to collaborate with her rival in Japan. Over time, her abrasive edges soften as she forges a strategic rivalry with Kanon and Tomari Onitsuka, forming a group to challenge Liella!—a calculated move to elevate both teams’ artistry through competition. Though their clashes remain respectful, the groups eventually merge, solidifying her growth from solitary ambition to valuing collective success.

Born January 20 under Aquarius with blood type A, Wien’s musical talent—her "excellent sense of music" and "fantastic singing voice"—is repeatedly emphasized, tracing back to childhood. Her arc reconciles relentless drive with the series’ ethos of unity, culminating in her embrace of school idol culture not as a stepping stone, but as a worthy pursuit in its own right.