Rui Kamishiro, a respected samurai who got hired by the Tenma clan to protect their eldest son, a man feared by many and envied by others. His life was always surrounded by danger and adventures, even protecting Tsukasa brought some challenges, he didn't expect the clan to be that threatened daily.
Rui always wears a mask and never allows anyone to see his face, making some people, Tsukasa being one of them, wonder what he could be hiding.