A Chou is the village's biggest good-for-nothing. With his dantian shattered, anyone can bully him.
Then, on the night his village is destroyed, ten rogue cultivators slaughter everyone. A chaotic vortex suddenly bursts open inside him and devours all ten enemies, each a hundred times stronger than he is.
From then on, a Myriad Demon Compendium appears in his palm. Every demon he devours unlocks a page of demonic arts and adds to his strength. A wildcat spirit grants speed, a thunder leopard grants explosive power, a fire crow grants blazing flames, and a flood dragon grants the power to overturn rivers and seas... A hundred common demons, a thousand spirit demons, ten thousand celestial demons, until he devours his way to the Immortal Emperor.
There's also an old geezer in his head who calls himself an Immortal Venerable and keeps saying, “Ten years of your cultivation can't match one glance from him.”
A Chou says, “Shut up. I'll do it myself.”
The Myriad Demon Compendium: Immortal Venerable Parasite. The story of a good-for-nothing who devours myriad demons to become an immortal.