Yahiko is a samurai descendant. Yahikos father died during the Battle of Ueno during the Boshin War slain at the Keneiji Temple. His mother died of syphilis in a brothel to put food on their table not long after giving birth to her son. Yahiko was originally forced to live as a thief for the local Yakuza who tricked him into believing that he still had to pay off the money the gangsters gave to his mother to buy medicine. With the help of Himura Kenshin and Kamiya Kaoru he becomes an apprentice of the Kamiya KasshinRyu style. Yahiko has a friend/rival Tsukayama Yutaro and a sweetheart Sanjo Tsubame who works at Akabeko.