Third season of Mushoku Tensei: Isekai Ittara Honki Dasu.

The sorcerer Luck believes this to be the end. Besieged by powerful demons, he makes the noble sacrifice of holding back their onslaught while his friends escape. Never sleeping or resting, Luck endures the clash of swords, rain of blood, and never-ending stream of enemies. Against all odds, he vanquishes the commander and emerges victorious, only to find that 10 whole years have passed in the meantime. Furthermore, his body has regressed in age to the point where he looks like a mere teenager. Following his triumph, Luck soon reunites with his friends, the hero Eric Imgard Mendirival and warrior Goran Morton. As they believed Luck to be dead, the pair made sure he went down in history as a hero and prepared to quell the rise of the demons themselves, unaware of Luck's feat. With all this in mind, Luck just wants a laid-back life, so he applies as a novice adventurer under the name Lock and sets out on a journey alongside brand new companions.

In this world, the concept of levels exist. Other than those who live off defeating monsters, most people are only around level 1 to 5. What's more, not just anyone can go out to hunt monsters; it's heavily influenced by one's role anointed by God. There are eight such eligible roles. Warrior. Fighter. Cleric. Magician. Rogue. Merchant. Hunter. Sorcerer. Those blessed with extraordinary power are divided into three types. Royalty. Heroes. Sages. But for the majority of the population, they have no such powers and live by farming or running shops. Towns are developed by those with the weakest role...villagers. For the powerless villagers going out to hunt monsters is equivalent to committing suicide. But one day, a certain two-year-old child given the role of villager notices something. Once you defeat a monster... you can earn great wealth.

After the mysterious mana calamity, Rudeus Greyrat and his fierce student Eris Boreas Greyrat are teleported to the Demon Continent. There, they team up with their newfound companion Ruijerd Supardia—the former leader of the Superd's Warrior group—to form Dead End, a successful adventurer party. Making a name for themselves, the trio journeys across the continent to make their way back home to Fittoa. Following the advice he received from the faceless god Hitogami, Rudeus saves Kishirika Kishirisu, the Great Emperor of the Demon World, who rewards him by granting him a strange power. Now, as Rudeus masters the powerful ability that offers a number of new opportunities, it might prove to be more than what he bargained for when unexpected dangers threaten to hinder their travels.