I Don't Want to Save the World, So I'll Train a Successor

(The protagonist retires) + (The protagonist is invincible) + (Multiple characters) + (Transmigration) + (Training disciples) + (Monster invasion)

After a car accident brought him to this world, the System granted Lei Fan the ability to cultivate and the duty to protect humanity. But when he saw primitive humans who had only just learned to make fire by rubbing sticks together, his expression turned sour! There was nothing he could do, though. In a world where monsters, demon beasts, and even aliens could descend at any moment, you either got stronger or died! To survive, he had to complete missions while growing stronger!

He dutifully protected humanity for five thousand years, until...

“What? My strength has reached its peak, and now it’s leaving me?”

“Damn, after five thousand years together, this stupid System still hasn’t warmed up to me!”

“But humanity has come a long way by now. Maybe it’s time I trained a few successors and thought about retiring?”