Rai-Dei is a samurai who seeks the knowledge learned only when facing death. He carries a sword with a built in gun that can be fired from the hilt, and is able to swing it with enough force to create a sonic blast. In the anime, he expresses anger in the fact that Vash is refusing to make his mark true and aim to kill, claiming he wants "a real battle."

In the manga, he wears "roller skates" that allow him to move at phenomenal speeds.

Rai-Dei is the protagonist of the 7th chapter of Trigun Multiple Bullets, "Trigun: Rising", which takes place before he becomes a member of the Gung-ho-Guns. In this chapter, Rai-Dei is protecting a small town from bandits and even training a young girl to succeed his "Jigengiri Ittouryu" fighting style. From the beginning Rai-Dei shows himself to be an apathetic person who kills anyone who crosses his path, but soon after he begins to show a little affection for the people of the town, a tragedy happens and Rai-Dei returns to his origins as an assassin, wishing cut more and more flesh with his blade.