As to the ghost, I had not planned on using them at all. It comes to my own personal feelings on the supernatural, which is why I will likely not use demons either. But the first book is actually designed to be a mystery were a regular human starts piecing things together on their own, but will find themselves in way over their head.

As for zombification, the infection starts to spread as soon as an individual is bitten. As part of how my version of the zombie virus will work it will kill off all but the most basic instincts in the brain. Basically just the need to feed. But it will not actually require death. Largely because I want to leave it open for the possibility of a cure. Basically my ultimate plan with the Zombies is to completely shatter the masquerade. The introduction of the zombies will basically start the final act.

Part of that stems from not having an outline. I do not like using them for writing, it takes away flexibility in my mind.

Let me sketch the basic plot out. This is a series of undetermined length as of now. One can imagine this as three phases or acts.

Act I serves as an introduction of the series. Effectively a character serves as an audience surrogate and discovers that there is a whole supernatural realm that has always existed alongside the world we know. Basically as a result of the Spanish Inquisition and Counter-Reformation a set of rules were put in place to keep humans and supernaturals safe from each other for the most part. This lead to a cold war between warring sides, and the supernatural began to fade into myth and legend. This brings us to the modern day. Where a veteran homicide detective gets a haunting case that seems to defy logic. She then stumbles upon an ancient conspiracy and then things happen.

Act II. The masquerade starts to break down. Regular people are getting suspicious not everything is what it appears. Our true villain is introduced. The Cold War between supernaturals heats up. All out war between supernaturals and humans is imminent.

Act III. All out war. I have yet to decide how this will end.

Ultimately the set up is that there is a masquerade that keeps the average person from realizing that there has been a war between supernatural forces that has been going on since the dawn of time. Essentially Order vs. Chaos. Not Good vs. Evil, because that's cliched. The lead up to the story set approximately now is that each group has their own things. The WWs want to be left alone, Vampires want to control everything and ensure their food source is well kept for. Angels are there to protect humans from everybody else.

Then along the course of the first book (I do not like planning out much further, because I like flexibility) only partially follows the protagonist, it is there to basically allow the readers to ask the questions. The main character in book one is basically a detective who stumbles across this ancient war and gets caught in the middle. The protagonist regardless of race wants to keep humans safe for one reason or another. If a Vampire keep the food source safe, Werewolf, would take more work but largely thinks if humans are safe less likely to hunt for his kind. Angel, it's his duty.

Any of the races will work. They all have reasons for wanting to keep humans safe and keep the status quo between sides. So naturally the masquerade will start to break down chaos will be unleashed and the protagonist and his organization will seek to maintain order.

Another way, is this a Vampire protagonist will have Blue and Orange Morality. A Werewolf will largely be a true neutral (just keeping me and mine safe) Order/Chaos or Good/Evil do not have any meaning for him. And an Angel will essentially be Lawful/Good.

Part of the entire premise of the story is breaking down the barriers on the sides. Ultimately a big bad is going to come along and threaten the entire world. And the disparate groups will need to come together to stop it.

As for relations, a rough timeline can be sketched out. From the beginning of the conflict Werewolves and Vampires have been at war. Kind of the standard Fangs vs. Fur that originated from a misunderstanding and the fact that the Vampires looked at the wolves as nothing more than animals that threatened their livestock. Angels were always present in small numbers (roughly 20 worldwide kind of thing) to try to keep humans safe. Up until the Spanish Inquisition there was a very broken masquerade, then during that time period it came to a head, and the Inquisition's real purpose was to cut down the numbers of the supernaturals (a Knight-Templar Angel was leading it). The Angels fractured and seemingly disappeared while the Werewolves/Vampires essentially agreed to truce and a cold war has been going on ever since. Skip to the modern era and someone is playing the sides off against each other to start a war between all the races that will likely wipe out humanity.

As a result of this, the time the book starts at an organization has been formed by representatives of all three groups to try to keep order. Naturally millennia old grudges do not go away so easily so there are external and internal existential threats to the organization. Basically any of the three could work, which is why I am asking.