A brief description of the light novel Unable to Cultivate, I Can Only Raise Soul Pets:
The former Immortal Ascension Realm Cultivator Wang Che failed to overcome the Heavenly Tribulation, and as a result, his soul transmigrated to a world of the Martial Soul where soul beasts and humans lived together peacefully.
After confirming that he could not cultivate in this world, the depressed Wang Che had no choice but to adapt to this world.
So…
“Caterp… Green Caterpillar, million years evolution!”
“I choose you! Rayquaz… Wait no, Sky Dragon!”