The Brave’s Ending Note Manga
Brave's Ending Note / Death Preparation Hero / The Brave's Ending Note / Tsuikatsu Yuusha / 終活勇者

Decades after defeating the Demon King and bringing peace to the world, the Hero is old and can barely remember his spells. When remnants of the Demon King’s army attack him, he sets out on another journey. This time, he is not trying to save the world. Instead, the Hero calls it a “death preparation journey”: a chance to look back on his life as he faces the years ahead.