Shijin Numa ni Yuurei Shoujo ga!!

Old man Gen, who lives alone in a church on the outskirts of the village, is a cantankerous eccentric. He meets Youko, a girl who says she’s been all alone since her mother died. After taking Youko in, Gen finds new joy in his life. But one night, he notices that Youko has gone out alone. The following night, when he follows her, he finds her at the edge of Death’s Marsh—a place plagued by accidents—where she is meeting her mother, who was supposed to be dead. Gen realizes that this is not a living being; in fact, it is the Grim Reaper.

(Source: Kaiki Manga no Anagura, translated)