Longevity Beast Contract

Overworked Gu Qingyu transmigrates and becomes a county constable in Da Wei. Cursed with a fatal fate, he only has three days left. He awakens an animal-taming longevity system and bonds with a black tortoise to share its lifespan and secret arts, gaining fifteen extra years. He and his companions solve supernatural cases. When a powerful monster attacks, his friend Qian Shan dies protecting civilians. Gu Qingyu slays the beast, takes an orphan girl as apprentice, and is recruited by the Demon Suppression Bureau. He advances steadily while his tortoise evolves, stepping close to the innate realm.