The Demon Lord's Darling Wife Builds Infrastructure in the Mortal Realm

The night I was transmigrated into the Demon Lord’s 999th concubine, I ran away under cover of darkness and fell into the mortal realm. I’d planned to laze around in this lower realm, where spiritual energy was scarce, but the mortals here were still making fire with sticks and keeping records with knotted cords. With winter approaching, I casually drew a fire-element formation to keep warm, only to be worshipped as a deity by the locals. When the Demon Lord tracked me down by following the fluctuations in spiritual energy, I was busy leading my followers in building irrigation works, roads, and a city. He pinched my cold-red fingertips and chuckled. “Is my runaway concubine building herself a betrothal gift down here?”