Majo no Ending Note

Twenty years after the Demon King was defeated by the Hero's party... Dyd, a mortician working at his family's funeral home, encounters Nina-Nina, the legendary witch from the Hero's party. She also happens to be Dyd's "first love." Though she looks like a young girl, Nina-Nina has lived for nearly 2,000 years. Due to the nature of witches, who bring about a calamity if they die leaving behind regrets, the request Dyd receives is to help with her "end-of-life planning"...!?

(Source: Square Enix, translated)