TL;DR: Explain the mysteries.
In this article, I’m going to teach you how to build a convincing mythos for your fictional setting.
There are loads of articles out there on the internet that do this. So I’m going to one-up them: I’m going to teach you, and I’m going to build a mythos from scratch as we go. That way, you can see, first-hand, how a system of myth and legend is built, from the first brick. Hopefully, what we have in the end is pretty good, too. If it is, maybe I’ll return to it in future articles.
Let’s get started.
The main role of myth in a belief system is to answer the unanswerable questions. The obvious questions are things like: Why was universe created? Why are people born? Why do bad things happen? Etc. But they can also be more mundane questions: Why does the wind blow? What is gravity ? Why do we have day and night? In most beliefs, there are answers to all these questions. And these answers often personify these things, too: the sun and moon being drawn across the heavens by gods in carriages, things like that. By personifying these mysteries, they make them less intimidating.
Assuming your world has linear time (and if it doesn’t, I hope you know what you’re doing), you’re going to need to explain why the universe is. This explanation doesn’t need to be correct, of course: they might be worshipping the death god Zurz as the benevolent creator of the universe. Or they might think the universe was created through entirely natural, scientific means, right up until they’re smited by a neglected (and very irate) creator god. The point is, belief systems don’t have to be correct to be believed in: they just need to make sense. Though if they are correct, that’s obviously a boon to them.
Let’s put this into practice.
Let’s say there are a race of goblins living in a jungle on a world with a very thin atmosphere and two suns. The first thing we need to know is where that world came from, and what the goblins are doing there. Now, unless these goblins are very advanced, they won’t have the tools they need to answer these questions scientifically. So they will turn to other means to explain their situation. So what evidence do they have access to? Well, they can see the stars and the dual suns. They see a sky full of glowing lights, and two are much bigger than the others. Perhaps they assume that the lights are spirits. And perhaps they assume that, once upon a time, all the spirits were the same size. So, somewhere along the way, two of them became more powerful than the rest. How they did so, why, and what that means can then become the basis of a belief system: perhaps one sun is a good god and one is evil, or maybe they’re two sides of the same coin. A natural continuation of this, however, is that these two spirits were somehow involved in the creation of the world. And they have the evidence for this belief: the spirits are always there in the sky, above the world.
For this example, I’m going to go with the idea that these two gods are eternally feuding spirits, each endlessly trying to get one up over the other.
You’ll notice, however, that I don’t discuss how the universe was actually created. Instead, I take the evidence available to a culture and use it to string together a convincing narrative. This is how to build the core of your belief system: try to use the available evidence to explain the existence of the universe. You can go into further details later.
Now you need to explain why the goblins are there. Usually, belief systems apply purpose to life, giving people a goal to strive for – either individually or for their whole race. People don’t like to think their lives are meaningless. So, now that we have a universe created from the energy of two feuding gods, we should tie the goblins into this narrative. Perhaps they were created by one of the gods (or, hell, both. Yes, let’s go with both) to fight their battles for them.
Let’s put a story behind this. What other evidence do we have to draw upon? Well, one of the usual tropes about goblins is that they are divided into clans, so let’s use that.
Say, after one particularly gruelling battle – one which ended, as always, in a stalemate, the two god-suns decided to call a truce. They came to the conclusion that they needed a different way to settle their differences. So they put their powers together and created the goblins, sentient beings who could observe and understand the gods. Instead of fighting each other directly, the gods would use their influence to draw goblins to their cause, and use their powers to help their loyal goblins win battles. This gives the goblins a purpose in life – to fight for the dominance of their chosen god – while also enhancing the two-gods-fighting-eternally narrative that we’ve just developed. It also gives the goblins a reason to be loyal to their clan and their god: loyal goblins are more likely to survive battles (whether this is actually true is completely moot). This would probably encourage the development of a class system, so we can actually do some worldbuilding for the goblin culture here, too.
Now that our mythos has given the goblins a purpose in life, we can move on to answering the smaller questions. Where do mountains come from? Things like that. This will all depend on what other features there are in your story. In general, you’ll need to think about the things that your people encounter on a daily basis – everything from complicated and troubling things like other people with other beliefs to mundane and simple things like water and landmarks. If you plan to do all these things in one go, it can take a long time, but I find that, once I have the basic mythos established, the answers to these questions come automatically when they come up. So I’d recommend only answering these questions as and when you need to, thinking about the things you’ve already got.
In the case of the goblins, maybe we should draw on the epic battles between the two sun gods a bit more. Perhaps the rain is the sweat from their eternal struggle. Perhaps they grew bigger by drawing on the powers of other spirits as they tried to become more powerful than each other. The mountains are scars in the landscape caused by particularly vicious celestial wrestling matches. One can imagine a rich oral tradition, full of epic tales and poems about how various competitions between these two gods caused the creation things like forests or gravity – as they tried to out-do each other or just beat each other to a pulp.
These are all details you can sprinkle around your core system once you’ve got it: maybe base it off of the traits of the race you’re working with (in this case, a mythos about the world being created by war and conflict seems very fitting for a warlike race such as goblins).
You don’t need to go into detail like this about every little thing in the world. You simply need to get to a point where, if a character asks another character who believes in your mythos about any of these things, you will know what the answer could be. Of course, feel free to go and worldbuild as much as you like. I’m just saying that it probably isn’t necessary beyond this point.