Figuring Out The Science

In the midst of creating this world, I realized that it needed a scientific side as well. It also needed to keep some level of historic accuracy as far as scientific discoveries went.

A simple example: At the time of the plague in Europe, no one really knew how it was spread. That was one of the reasons it was so deadly. If I have a character start washing their hands and such, I've jumped quite a bit into the future. "Sanitary" isn't really a word one associates with that time period.

This lead to another question from myself to myself: are the Immortals in any way ahead of humans as far as scientific discoveries? The answer here is yes, but not by much. In fact, by the time we get to the present, humans and Immortals are about even in the "discovering things" category.

Then came a third question: What makes the Immortals, well, immortal? I could take the easy way out and just say "magic" or something, but I want to get a little more complicated. Their genes are different. Just as their are genes for eye color, possible mental illness, and height, there are genes that make one simply not age...or just age very slowly.

In humans, this is a mutated gene that often leads to aging disorders like progeria, DKC, and the like. In Immortals, the gene is always inherited and combines with another gene common in all Immortals to create the immortality. This isn't pure immortality, though. Immortals can age, but it happens so slowly that it is almost at a stand still. The twins are over 400 years old by the end of Book One, but they do not look over 20 years old.

Here's the kicker; there are certain substances that hold off aging, so Immortals have the option to age a bit for appearance purposes or continue looking 18. For Dark Ones and Vampires, it is blood. For Shadow Walkers and Felians, it a being's life force. For Night Wolves and Werewolves, it's flesh (so sorry, no vegan or vegetarian Night Wolves exist). And yes, for all of them, human is best because of the genetic similarities.

I probably went into this WAY more than I needed to, but it helps to know the rules of your story. Fans of your work are less likely to, I don't know, come after you with torches and pitchforks that way.