Ryōma Sakamoto carried the green legendisc, and used the power it gave him to become an invincible swordsman. When Isami and the Samurai Team arrived in his time period, he was dueling a severely outmatched opponent. When Isami stepped in to protect his victim, Ryōma refused to believe that anyone could want the power of the legendiscs for a reason other than their own gain and challenged Isami to a duel for control of both the red and green legendiscs.
When their duel was interrupted by the arrival of the oni Budora and Bakudora, Isami stepped in to protect him. This proved to Ryōma that Isami's intentions were genuine, and he gave his disc to Isami. When Isami and the Samurai Team returned to their own time, Ryōma swore to become strong to protect humanity and the Earth just like Isami.