I Grow Stronger by Sacrificing Others, Staying Hidden Until I'm Invincible

He transmigrates to a fantasy world where demons and monsters run rampant and the land is in chaos! He obtains the Sacrifice System. Sacrificing demons and monsters earns him rewards, making him stronger and stronger! Nie Feng is full of lofty ambitions, but reality hits him hard. He nearly dies at the hands of a powerful demon! So he decides to lie low in a small city, sacrificing endlessly and staying in hiding until he's invincible before venturing out.