奴隷勇者の異世界譚～勇者の奴隷は勇者で魔王～ (Associated Names)

Middle schooler, Hadzuki Jin, was summoned into another world as a hero but sent back to the original world without being able to protect many important things. After sent home, memories faded away as if it were a dream, and in his own helplessness, only the ring given by the summoner princess remained. Three years…