Sam Ichijouji (一乗寺 治 Ichijōji Osamu?) is Ken's late older brother. He was three years older than Ken.

Sam was a child prodigy and got a lot of attention because of it. His parents often ignored Ken, who became jealous of his older brother. When they were young children, the brothers got along well, and they would often go out to the balcony to blow bubbles together. Sam wasn't as good at it as Ken; Sam said it was because Ken was far gentler than he was.