Yui Ichimaru (市丸ユイ, Ichimaru Yui) is Britannia's leading female bio-engineer, despite being half Japanese, as well as the creator of the twin Knightmare Frames known as the Silverhawk and the Goldhawk. Ever since Kanna's soul was given to the core of the Silverhawk Yui has been taking care of Akashi, Kanna's daughter.
Yui's hair is rather a brownish red, short and very messy. Her eyes, inherited from her Britannian parent, is a piercing green and she has been complimented quite a few times because of their clear color. While at work she always has her white lab coat on but in private surroundings she often dresses in baggy clothes.
Yui has at times been occupied with her work to the point of obsession but usually maintains a healthy distance between work and sparetime. She has been described by Akashi as a kind and patient, yet stern, woman who always has time to listen if there's someone with a problem.