Unsō-ya no ossan ga naze ka fukugyō de zettai muteki kenshi o tsutomeru koto ni ~ sae nai jinsei o okutteta ore ga maō tōbatsu no kirifuda ni?~

Alternative

The Middle-Aged Delivery Man Who for Some Reason Ends Up Working as an Invincible Swordsman on the Side ~ Will I, Who Has Led a Boring Life, Become the Trump Card To Defeat the Demon King? ~ ; 運送屋のおっさんがなぜか副業で絶対無敵剣士を務めることに～さえない人生を送ってた俺が魔王討伐の切り札に？～