Kei is a woman of average height with a slim and narrow build. He himself has pointed out that his back muscles are not broad enough (though this is more of a metaphor portraying his lack of ability to lead and provide stability). He has feathery, ash blond hair that is swept messily backward, with some of the front tufts sticking up in arcs above his head. His eyebrows are notably thick, having a similar appearance to his hair, and he has faint stubble on his chin.