World building & lore

Zombies are one of the only species that can only occur artificially! The others being Androids and Homunculi!
there are special blood banks specifically made to distribute blood to vampires. A vampire can choose what blood type they want to drink and then has to pay a small fee (around $8) to buy a month's supply.
When born, shapeshifters will look like a small dragon-like creature that is pitch black save for small white stripes around the tips of the tail and horns. As they grow their default form will adjust based on what they were raised around, a default form will nearly always have some form of tail or horns though.
Ghosts do not typically reside in Hell and instead have their own World which is a vacuum that expands infinitely outward to accommodate for the never ending amount of souls that join. Ghosts have fully built cities, jobs, and businesses where they can do whatever they please. Grim reapers tend to live here too.
Demons and ghosts are fully capable of entering the human world through hot spots, checkpoints, and purgatories (eg Alkatraz, Onigashima, ect)
There is a hotel chain that only appears in purgatories that is there to help people figure out the circumstances of their life and to help them pass onto their respective afterlives.

Historic timeline