Lingyin Huang, often called Rin, is a first-year student at the IS Academy and the second childhood friend of Ichika Orimura. She is the IS representative candidate for China and pilots the personal unit Shen Long. During her middle school years, she was frequently bullied because of her nationality, but Ichika stood up for her and protected her, which sparked her deep affection for him. As a result, she made a promise that if she could cook well for him, he would marry her, though Ichika misunderstood this as an offer of free meals. Lingyin comes from a family that runs a restaurant, and she is a naturally gifted cook.

Her personality is bright, bold, and extremely energetic. She is straightforward and rarely hesitates to speak her mind, often acting on impulse without fully considering the consequences. This impulsiveness can make her seem brash or rough around the edges. She has a competitive streak and a hot-tempered nature, and she is prone to jealousy when Ichika shows attention to other girls. Among the cast, she is known for being the most physically open with him, although the interactions remain mostly platonic. She is also sensitive about her flat chest, which is a frequent source of embarrassment and irritation for her.

Lingyin’s primary motivation is her desire to be close to Ichika, stemming from her childhood crush and the promise they made. She joined the IS Academy shortly after Cecilia Alcott became part of the group, adding herself to the circle of girls vying for Ichika’s attention. Her role in the story is that of a rival childhood friend and a capable pilot who often uses her combat skills to protect or impress him. In battle, she relies on her impressive physical prowess, including outstanding agility, sharp dynamic vision, and powerful kicking techniques. Her IS aptitude is ranked A, allowing her to operate a personal machine effectively.

In terms of development, Lingyin learns to channel her impulsive tendencies through her training and interactions with other cadets. While her jealousy and competitiveness remain strong traits, she gradually becomes more aware of the feelings of those around her, though she never fully abandons her straightforward, energetic approach. Her key relationships include her bond with Ichika, which is the emotional core of her character, and her rivalry with the other female pilots, especially Cecilia, Houki Shinonono, and Charlotte Dunois. She also serves as the class representative for Class Two, a position that reflects her leadership qualities despite her sometimes reckless nature.