Tribal System: Conquering the Wild Women with my Club

A brilliant mechanical engineer dies the most fitting death for his scandalous reputation distracted by the plant manager's breathtaking ass, he completely misses the pressure gauge warning, and the boiler blows him to smithereens. Instead of the afterlife, his soul transmigrates into the body of “Little Flame” a frail tribal youth who just kicked the bucket from an overdose of mystical Night Lily powder. To his absolute bewilderment, he wakes up inside a primitive hut with his voluptuous aunt desperately riding him, trying to get pregnant so the tribal chief won't sell her off as livestock. Armed with the mind of a modern engineer and a newly awakened “Tribal System” that demands he expand his territory and his bloodline, the new Little Flame decides to seize control. The weak boy of the clan is gone, it’s time to use modern technology to drag this tribe out of the Stone Age, crush rival clans, and conquer the wildest women of the untamed lands. After all, to build an empire from scratch, a man needs two things a heavy club to smash his enemies, and an equally relentless “club” for the sheets. [Kingdom Building - Wild Harem - Explicit Smut - Technological Progress]. — Description from novelcodex.org