Why Do All These Monsters Have Health Bars?

Yang Fan transmigrates to a fantasy world and is astonished to discover that he can see everyone's health bars.

As long as he keeps hunting demonic beasts and slaying his enemies, his own health bar will keep growing.

Many years later, he looks back. The grass on his former enemies' graves has grown several meters tall, yet he is still there, high above, looking down on all living things.