For more than 30 years, Dariel has been a loyal soldier in the Demon King's army, having been raised by Granbarza, one of the Four Heavenly Generals. However, as Dariel lacks any magical potential, he is nothing but a disgrace in the eyes of Granbarza's son, Bashbarza, who fires Dariel right after assuming his father's position as a general.

Stripped of a home and a job, Dariel wanders the forests, where he stumbles upon a human girl named Malika running from a monster. After Dariel intervenes to help Malika, she invites him to stay at her village in return. There, he discovers that the reason he has zero suitability for magic as a demon is that he is, in fact, a human.

However, Dariel is no ordinary human. Possessing potential that far outweighs even heroes, Dariel may soon find himself involved in the humans and demons' seemingly never-ending conflict, facing against the race he once considered allies.

Kaiko sareta Ankoku Heishi (30-dai) no Slow na Second Life was released on Blu-ray in four volumes from March 22, 2023, to June 21, 2023.