Yuusha ga Shinda!

From Shogakukan:

Touka is just your average (slightly perverted) farmer in the village of Cheza. While he daydreams about being a hero and getting the girl, the real hero, Sion, is out battling demons that threaten to invade the world. But one day, Touka accidentally kills the hero. With the Legendary Hero dead, who’s going to save the world now? Touka quickly buries Sion’s body to hide the evidence but wakes up the next day to discover he is no longer in his own body.