The male protagonist of Girly Air Force. Kei was just a normal teenager until his life was changed forever when his homeland was attacked by mysterious invaders called the Zai. When he and his friend Minghua attempt to escape from the Zai, they are saved by a crimson fighter aircraft that easily defeats the invaders and crashes into the sea. Kei rushes towards the fighter and attempts to save the pilot, only to find a girl inside the cockpit.

Much later, Kei has decided to join the Japanese military and tries to investigate about the fighter that saved him. Upon spotting the mysterious aircraft that saved him being held at a facility, Kei attempts to infiltrate it but he gets captured by soldiers. They tell Kei that the fighter he is obsessed with a special aircraft called a Daughter, and for some reason, he was able to get it to fly properly. They offer him the chance to join the military and introduce him to the pilot that saved him, a girl called Gripen.