History of the World
Two beings come to existence representing Light and Darkness called Ilias and Alice. Ilias creates the Heavens and the Earth along with the beings that inhabit it such as gods, angels and humans. Alice creates a Hellish realm with beings known as monsters that eventually start to also reside in Earth as well.
Some humans, plant, and animal life get 'infected' and start to become monsters themselves. Angels and a few minor deities 'fall' and become something similar to monsters.
After years of tension between Heaven/Earth and Hell the humans, angels, and gods went to war against the Demon Lord and her monstrous army. Eventually the two opposing forces realized that there will not be any winner and the war ends with the races coming to a peaceful conclusion.
An incident with the new Demon Lord causes a rise of the female population, turns more beasts into monsters, and a decline of the male population. Humanity faces the possibility of extinction due to being outbred by monsters.
'Purists' and Extremists factions cause a problem for the overall monster population.
Monsters continue to evolve with new species practically popping up on an almost yearly basis.
Species of monsters that were thought to have gone extinct have turned up.
A new type of male species called 'Incubus' has been discovered. With their appearance humanity has been giving breathing room and allow them to recover their numbers.
In the present day angels, gods, monsters, incubi, and humans live in peaceful harmony.
Author's Notes
Hello guys! Now this isn't so much as a story as it is so much as an encyclopedia of different Monster Girls. I was inspired by Omega E The Reader's Fanmade Monster Girl Encyclopedia.
The current setting that the codex takes place is a Monster Girl Encyclopedia and Monster Girl Quest with elements of Daily Life with a Monster Girl, Monster Girl Doctor, My Girlfriend is a T-Rex, Killing Bites and Rosario + Vampire.
As you can see, like my other Monster Girl fanfic Ilias is not as insane and deplorable as her canon counterpart and has made true peace with the Monster Girls.
The monsters featured in this will be monsters and animal from across different shows, movies, video games, etc such AvP, Monster Hunter, Godzilla, Mario, etc that will be heavily modified to fit this universe. Of course some monsters that I'll be putting in there won't be a s heavily modified due to how their canon counterparts wouldn't be out of place if they were put in a Monster Girl setting.
Before I forget: To whatever fanfic author or someone who wants to write their own fanfic someday, I give you guys my FULL permission to use the information I'm providing for their own Monster Girl fic. It'll be fun to see it. You do not need to PM me or ask me in a review, you guys can go ahead and use it.
Now for my first entry :)