Noroi no Sei de Yuusha Party wo Tsuihou Sareta Ossan Senshi, Ryoushu ni Natte My Pace ni Henkyou Kaitaku wo Susume Teitai Hazu ga Tsuyosugite Bakusoku de Ryouchi ga Hattenshita Ikimasu

There was once a man who effortlessly brandished a colossal blade, cutting down one enemy after the other. He was feared as a war demon, a warrior on the same level of the Hero, the mightiest there was... But that was in the past. Now the middle aged man Vald is scorned as a coward who hesitated before the Demon King, and he was given nothing but a remote territory for his past glory. Due to a powerful curse cast on Vald by the Demon King's army at its last moments, his body became incapable of fighting. Even the territory he was given is in ruins was torn apart by monsters... And on the very day he arrived to take up his land, monsters launched an attack on his territory right before his eyes. "I'd convinced myself I didn't care anymore..." So, even with his cursed body weighing him down, Vald draws his beloved sword once more to protect the people. Can he protect his territory from the grasp of evil? Marked by a curse, the strongest middle-aged man's battle begins once more.

https://www.manga-up.com/titles/1681