I’m a Demonic Cultivator with a Planet of Zombies

What happens when a young man who transmigrates into a world of immortal cultivation becomes a demonic cultivator, then discovers he can also enter a post-apocalyptic world?

He trades goods between the two worlds, collects merit, awakens special abilities, practices demonic sect techniques, and builds his own power...

But this is only the beginning. Immortal maidens and demonic enchantresses are waiting for him, too...