Ibuki Niijima is a central character known for her role as the leader of the music group Photon Maiden. She is a student at Yoba Academy, where she also holds the position of student council president and serves as the group's producer. Born on April 10th, she stands 165cm tall and has a blood type of A. Her appearance is defined by her grey hair, which is almost always tied back in a tight ponytail, parted front bangs, and blue-grey eyes.

From a young age, Ibuki has always loved being active and participated in numerous sports throughout her childhood. It was during junior high school that she discovered a passion for dancing and singing, leading her to enroll in a performing arts school. This background in athletics and performance heavily shapes her personality; she is a very proactive and energetic individual who naturally falls into the role of a mentor and a caring big sister figure to those around her. Despite her leadership qualities, she also possesses a modest side and can be somewhat embarrassed by direct praise or recognition of her popularity.

Her primary motivation stems from a deep-seated desire to support others. She never forgets to care for her friends and groupmates, embodying her leadership title in both name and practice. A significant part of her drive is ensuring that Photon Maiden lives up to expectations, originally set by the group's former producer, Himegami Shano, whom Ibuki greatly admires. After Shano's departure, Ibuki steps into the role of producer herself, taking on the responsibility of being a pillar of support for the group and working diligently to address the challenges they face.

Within the story, Ibuki's primary role is as the steadfast anchor for Photon Maiden. Her leadership is crucial in guiding the unit and helping each member grow, both as performers and as individuals. This is particularly evident in her relationship with fellow member Saki Izumo, who she consistently supports in finding her own artistic identity and new creative directions. Her key relationships extend beyond her unit. She is close friends and training partners with Sasago Jennifer Yuka and Matsuyama Dalia, who she regularly exercises with at the gym. Ibuki also develops a friendship with Saori Hidaka, who respects Ibuki's positive and hardworking attitude, and she later becomes classmates with the character Weronika. Within Photon Maiden, she balances her caring nature with a sense of discipline, scolding Towa Hanamaki for recklessness like eating too many sweets before a performance, while finding herself perplexed by Noa Fukushima's intense obsession with cute things, just as Noa finds Ibuki's passion for fitness unusual.

Throughout the narrative, Ibuki shows clear development as she transitions from being a supportive leader to also taking on the producer mantle. This evolution is partly influenced by her admiration for Shano, as she subconsciously begins to emulate the former producer's traits while working to fix the issues Shano had pointed out in the group. Her abilities are rooted in her extensive physical training and performance education. She is a skilled dancer and singer with a strong grasp of sports science and team management. In fact, she serves as the manager for her school's track and field team. Her commitment to physical fitness is notable; she maintains a healthy diet and is knowledgeable about exercise, though she is also known to possess a surprising ability to eat large quantities of food in a contest, which she rarely does because of the effort required to burn off the calories afterwards. Her family also owns a shrine, and she occasionally assists there as a miko.