Rurouni Kenshin: Reflection (2001)

Original title: るろうに剣心 -明治剣客浪漫譚- 星霜編

The Final Atonement

Kenshin and Kaoru are married. Kenshin leaves Kaoru with their son, Kenji, to lead a revolution in China. But both of them suffer from a seemingly incurable disease. 15 years later, Kenshin tries to return home to his wife before she dies of grief. Flashbacks of Kenshin's previous encounters with friends and foes occur while Kenshin struggles to make it back home.