Reborn as a Turtle, Why Is There a Person Living on My Back?

After an accident, Lu Xing was reborn. But before he had time to be happy, the reality of the situation had already slapped him hard, and he became a turtle directly after rebirth. He thought there was no hope in this life. Until he discovered that there was a primitive tribe living on his back! When his tribesmen sacrificed, he became stronger. As the tribe grows, he evolves. One day, he will carry the entire tribe and grow into the strongest civilization in the world! (The protagonist will not change into a human)