The Middle-aged Deliveryman Becomes an Invincible Swordsman as a Side Job Unsouya no Ossan ga Nazeka Fukugyou de Zettai Muteki Kenshi o Tsutomeru Koto ni ~Saenai Jinsei o Okutteta Ore ga Maou Toubatsu no Kirifuda ni?~

También conocida como: The Middle-aged Deliveryman Becomes an Invincible Swordsman as a Side Job ~After Leading a Lousy Life, I’m Now the Trump Card to Defeat the Demon King? · Unsouya no Ossan ga Naze ka Fukugyou de Zettai Muteki Kenshi wo Tsutomeru koto ni: Saenai Jinsei wo Okutetta Ore ga Maou Toubatsu no Kirifuda ni? · 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？～ · The Middle-Aged Deliveryman Becomes an Invincible Swordsman as a Side Job: After Leading a Lousy Life, I’m Now the Trump Card to Defeat the Demon King? · Unsouya no Ossan ga Nazeka Fukugyou de Zettai Muteki Kenshi wo Tsutomeru Koto ni: Saenai Jinsei wo Okutteta Ore ga Maou Toubatsu no Kirifuda ni? · Unsouya no Ossan ga Nazeka Fukugyou de Zettai Muteki Kenshi o Tsutomeru Koto ni ~Saenai Jinsei o Okutteta Ore ga Maou Toubatsu no Kirifuda ni?~ · The Middle-Aged Deliveryman Becomes an Invincible Swordsman as a Side Job · The Middle-Aged Deliveryman Becomes an Invincible Swordsman as a Side Job ~ After Leading a Lousy Life, I'm Now the Trump Card to Defeat the Demon King? · 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? · Unsouya no Ossan ga Nazeka Fukugyou de Zettai Muteki Kenshi wo Tsutomeru Kotoni · Unsouya no Ossan ga Nazeka Fukugyou de Zettai Muteki Kenshi wo Tsutomeru Koto ni - Saenai Jinsei wo Okutteta Ore ga Maou Toubatsu no Kirifuda ni? · Unsōya no Ossan ga Nazeka Fukugyō de Zettai Muteki Kenshi wo Tsutomeru Koto ni ~Saenai Jinsei wo Okutteta Ore ga Maō Tōbatsu no Kirifuda ni?~

The manga centers on Jack, a middle-aged freight company employee, who suddenly becomes the key to defeating the demon king, when he is told that he is blessed with the strength of a legendary swordsman. He then decides to become an invincible swordsman as a side job.