At first I thought she is just a minor character, created only to take up the empty space on Shishio's side to make him look even more like a villain. But I was very wrong; it turned out that not only she plays an important and impressive role but also I start to like her a lot, especially after I've watched her interaction with Sano in Shishio's hideout.
She's a nice woman with a sad past. Being a geisha, she never found any happiness until she met Shishio. Of course, she loves him with all her heart and is willing to sacrifice everything for him, even her life. Though without any fighting skills, she put herself between Shishio and Kenshin during their fight and begged Kenshin not to hurt her lover anymore. But Shishio pierced a sword through her body and managed to wound Kenshin badly. Yumi doesn't feel betrayed but is instead glad that she was useful to him. She last words are: 'I am glad. This is the first time that I am useful to Shishio-sama... and it's an important fight... every time Soujiro and Kamatari go out and fight, I could only tend to your health... I have been frustrated with myself... but now... please win, Shishio-sama... Yumi will be waiting in the afterworld.'
Isn't that so sad and touching?. She died an honorable death saving the man she loved. This is the woman who made an ultimate sacrifice: Komagata Yumi.