I'm Invincible, What's Wrong with Having More Adopted Sons?

Zhao Yifan was originally a horse in the 21st world. He suddenly died after receiving 200,000 overtime pay. He traveled to a world where martial arts was rampant, and was bound to the invincible system of many children and many blessings, so he began the path of cultivating his adopted sons. Of course, he also used his adopted sons to make his strength take off until he was invincible!