A Symbiotic Relationship

Wan Gu was climbing a mountain when a Flame Beast threw him into the magma, turning him into a skeleton spirit.

After regaining his body, he wanted to go home and take a look. But everything had changed, and the home he once knew was gone. Whenever the moon turned a strange shade of red, monstrous beasts would appear and invade human settlements.

With a human soul, he resolutely joined the force tasked with exterminating the beasts to protect humanity.

But his body was deteriorating. Once it was damaged beyond repair, he would have to leave human territory.

I... I can restore your body. You're really strong. Lots of beasts want to eat me. Can you protect me?

Qi An trembled as he emerged from a crack in the wall.

Wan Gu looked at the red mushroom spirit that had appeared. It was weak and helpless, yet somehow still brave. "I can."

The little mushroom trembled as it grew mycelium and took root in his body.

Theme: The soul that guards humanity's home will never perish.