In Yaiba

Soshi Okita is a participant in the Oda Nobunaga tournament who has a very laid back attitude. He made a promise with his grandfather that he could quit practicing kendo if he won the tournament. He disliked kendo because found it too easy. He encounters Yaiba in the fourth round when Yaiba trips over him while he is sleeping in the grass. When the two fought, it was clear that Soshi was the better fighter. Yaiba refused to give up and his death termination eventually led Soshi to forfeit the match. Soshi then decides that he will continue to practice kendo.

In Detective Conan

He looks like Shinichi and Heiji

He is the historical Okita Soji's grandson.

Soshi Okita III appeared in episode 71 of the anime Lupin III: Part II, a source of inspiration for Detective Conan.

(Source: detectiveconanworld.com)