Okay, this is the chapter that's mostly gonna connect with eventual crossover. It's not gonna be that long but I hope you enjoy. Also if you're wondering which fanfiction is crossing over with it's my Multiverse one. if you wanna go check it out, go check it out.
Narrators point of view

Rotten world, the world of the Horsemen of pestilence filled with zombies and undead creatures spread like a disease across an endless ocean of death each one of them waiting for the door to the living world to be open so they could swarm it and have a never-ending feast of human flesh

Of course the door was never open. There was only small cracks that formed allowing a few of them to slip through. It was only one time when the gates were open only for a brief 2nd to allow the elite war of the zombie army out but they were defeated by a bunch of zombie hunters.

The dead hunger for freedom like never before they wanted out they desperately wanted but all they could find with cracks just small enough for a few of them to slip on through and the bigger ones always took priority. They wanted their chance in the Sun to devour the Earth, fortunately for them Something was moving in across world making deals with certain individuals

The zombies didn't know what this thing was, but they were all too happy to make a deal with this Demon in red that arrived. The Horseman took it upon himself to negotiate.

The red Demon with a twisted smile : thank you for your cooperation unfortunately my friend in charge of our little band of lunatics is busy with another project right now but I promise you he will return and release you from your prison where you will have the chance to feast on whoever you desire you will never go hungry again