Yukishiro Tomoe (later Himura Tomoe) was the daughter of a low-ranking samurai family that remained on the side of the Bakufu during the Meiji Revolution and was engaged to her childhood friend Kiyosato Akira. However, when Akira was slain by the Hitokiri Himura Battosai (a.k.a. Kenshin), Tomoe leaves home and joins the Yaminobu in order to avenge her fiancé. However, after tracking Battosai down, she slowly falls in love with him instead. As the Yaminobu close their net around Battosai, Tomoe intervenes and, saving her new husband's life, becomes a casualty herself - cut down by Kenshin's own sword. As such, Tomoe becomes Kenshin's primary motivation in his oath to never take another life following the end of the revolution and devote himself to protect the innocent without bloodshed.
(Source: Kenshin.fandom)
