During the last story arc from the manga, the story takes a darker tone than those from other "shōnen" series published by Shueisha. As the series was aimed at teenagers, Watsuki made Yahiko the main character during the time when Kenshin thought that Kamiya Kaoru was dead; his role was to serve as the identifying character for readers. However, the author found this hard to do, as the more time Kenshin was unwilling to continue to live, the worse Yahiko felt, leaving Watsuki a more negative feeling concerning the story. By the end of the series as Yahiko becomes a teenager, Watsuki had redesigned his appearance. He wanted Yahiko to impress manga readers so that he could be a protagonist for a possible series sequel. He said this goal influenced his design of Yahiko, with Kenshin's physical appearance as well as Sanosuke's personality. He added Sanosuke's kanji of to the back of his clothes, and was pleased that various readers recognized it. Although he suggested he was not going to make a sequel, he said the main characters would be Yahiko, Sanjō Tsubame and Tsukayama Yutarō. Watsuki thought about writing a story in which Yahiko and Tsubame would have a son, Myōjin Shinya, who would become a skilled swordsman.