Chillin' in My 30s After Getting Fired from the Demon King's Army

Dariel, stepson of Demon Lord Granverza, is fired from the demon army by his stepbrother Bashvaza following Granverza's retirement, citing Dariel's inability to use magic. Homeless, Dariel wanders aimlessly until he meets a young woman named Marika fleeing a monster. Despite being unfamiliar with human weapons Dariel uses Marika's dagger and kills the monster. Grateful, Marika drags Dariel to her village. Hiding his demon identity Dariel only reveals he was fired recently. Marika's parents insist he stay with them and become a guild adventurer so he can protect the village from monsters. Dariel tries to protest as receiving a guild seal would expose him as not human, yet he somehow passes the test. Dariel realises that despite being raised by demons he must actually be human. Dariel learns of Aura, a human magic that boosts weapon abilities. Despite believing himself weak Dariel discovers he has an affinity for Aura making him a master class warrior. Marika's father suggests Dariel might be better suited to a larger guild in a city, but Dariel decides to stay in the village. Marika is overjoyed but the villages only other adventurer, Gashita, is unimpressed, until it is discovered the monster Dariel killed was one Gashita has failed to kill for over two weeks.

Dariel's first quests as an adventurer go smoothly, but the village's other adventurer, Gashita, continues to see him as the enemy. Word that a high level monster has appeared near the village arrives. Dariel heads into the forest to bring Gashita back.

Dariel learns that Lux Village once flourished due to a nearby mine. When the demons took it, they condemned the village to a slow death. As the mine is Dariel's old workplace, he decides to visit it to see if there's anything he can do for his new home.

Bashbarza is in a rage after being reprimanded by the Demon King for losing the mythril mine. Meanwhile, in Lux Village, the mood is a celebratory one. Dariel runs into an old coworker and sees an opportunity to prevent conflict between humans and demons.

Lux Village is starting to thrive, thanks to the Mythril Mine, but Fittbitan has taken control of the forge. The arrival of a legendary swordsmith makes Fittbitan view Dariel with even more hostility, and so the adventurer challenges Dariel to a duel.

Dariel is shocked at the identity of his unexpected sauna companion. How will this affect their future? Dariel stands at a crossroads in his life and Lux Village begins to change. Then, one day, Dariel hears that the Hero's party is visiting the village.

The Hero, Laidy, has two objectives: to have new mythril weapons made, and to find a new ally to help defeat the Demon King. Laidy becomes aware of Dariel's true abilities and asks him to join her party. Dariel declines, but Laidy refuses to accept it.

The General of Wind, Zebiantes, arrives in Lux Village with certain demands after hearing rumors of mythril. Even after Dariel manages to settle things with her, he realizes he has another problem—he can't let Laidy and Zebiantes clash!

The strongest Hero, Alantsil, has come to visit. Unable to forgive the demons for the tragedy in his past, Alantsil attacks Zebiantes. Dariel tries to convince Alantsil not to fight, but to no avail. As they talk, the secret of Dariel's brith is revealed!

Alantsil, the previous Hero, and Granbarza, formerly one of the Four Generals, confront each other. One wrong move could bring them to blows. Meanwhile, Bashbarza's hatred for Dariel explodes, and he heads off to do something about it.

Dariel and the others rush to the Mythril Mine on a rescue mission, but the Magical Fire Beast, Salamandra appears in their path. Dariel presses ahead with their rescue efforts, but Bashbarza, who has obtained tremendous power, has other ideas.

Humans and demons take a stand to protect what is dear to them. During the fight, Dariel comes into contact with Bashbarza's memories and the two men's emotions collide. What will be their future, and the future of Lux Village?