From Seven Seas:
The Tokugawa shogunate has fallen, and former samurai Haruyasu is adrift in a strange new world, searching for a place to die. But when he attempts to assassinate a government official, hoping this will bring the eternal peace he craves, Haruyasu finds himself at the mercy of the official’s bodyguard, a young woman who claims she’s the daughter of an immortal. What will she ask in return for sparing his life?

https://www.cmoa.jp/title/227027/