Kasumi Nakasu

Kasumi Nakasu is one of the original members who helped start the Nijigasaki idol club, and she throws herself into the idea of becoming a school idol with real passion. She can come across as mischievous and even a little mean toward girls she sees as rivals, often insisting out loud that she has a cold heart, even though her actions usually show the opposite.

She hates being called "Kasukasu," a teasing nickname that pokes fun at her name, and she tends to overreact to anything that looks like a challenge, sometimes to a comic extreme. At one point she completely misreads a farewell letter from a departing club member as a declaration of rivalry from an outside school, throwing herself into a dramatic response to a misunderstanding nobody else even noticed.

Despite the tough exterior, Kasumi is warm and loyal to the friends she makes in the club, and she later becomes part of a subunit called Qu4rtz together with Kanata Konoe and Rina Tennouji. Her arc across the series is largely about learning that being kind doesn't make her any less fierce as a performer, and that she doesn't need to act "black-hearted" to be taken seriously by the people she competes against.