Every time I run my game, it makes me want to write about, so here you go you lucky internet folk.
Specific definitions of elemental damage types come and go in D&D, but from the very beginning it has been explicitly built on a four-element metaphysics, consistent with, broadly speaking, Western civilization as influenced by the Greeks and Romans. The four familiar elements are earth, air, fire and water, and they are familiar to us even from diverse sources like Final Fantasy, board games, our four suits we use in card games (by “our” I mean Americans and Europeans, D&D’s main audience).
If we look out East, we find other metaphysical models for the elements. In Hinduism, broadly speaking again, you can say there are zero elements, or one element, or five, or six. When looking at the five-element and six-element models, they were imagined as concentric circles, or as increasing complexity, which wasn’t what I knew I’d need for a D&D game.
I was already quite familiar with Daoist elements, and some of you reading this might be as well from such sources as acupuncture and feng-shui. In the Daoist model, there are five elements, and each flows into the next, and then each is vulnerable to one of the other ones, making this model look like a complicated five-pointed star with a circle drawn around it, like this:
Adapting this to D&D took some doing, obviously. I had to think it through in light of the way that elemental damage works in 5E. Leaving out radiant (which I’m calling yang) and necrotic (which I’m calling yin), there are acid, poison, fire, cold, lightening, force, thunder and psychic. I also left off psychic for this system, since in the metaphysical model itself, all of the five elements have psychic/psychological elements.
Reading further in the area, I found some correlations that were consistent. Obviously, Fire coincides with fire. Similarly, Water coincides with cold. Metal, being a conductor, I decided would coincide with lightening. Wood is associated with storms and strong weather, so I decided it would cover thunder. Earth is associated with acids and chemistry, so I left that association in place. And since thunder and acid damage are relatively rare, I added force to thunder and I added poison to acid. So, in terms of the type of damage associated with each element, I got this:
Fire: fire; Earth: acid and poison; Metal: lightening; Water: cold; Wood: thunder and force. That’s in generative order. But each of the elements is also vulnerable to another. So, in thinking about supernatural creatures that are strongly rooted in one of the five elements – dragons, for example – I had to figure out what each one would be vulnerable to. This took a number of tries, but I ended up with :
Fire is vulnerable to cold; Earth is vulnerable to thunder and force; Metal is vulnerable to fire; Water is vulnerable to acid and poison; Wood is vulnerable to lightening (the least reasonable one at first glance, but necessary in the overall scheme).
This progression follows the overcoming/destructive cycle (the star above) exactly. Fire is extinguished by water. Earth is broken apart by wood (think of a tree root up the sidewalk). Metal is melted by fire. Water is broken up by earth (the sea hits the coast, the river held by the river bed, etc.).
An example of how this plays out is in the case of a Yellow Dragon or Earth Dragon. I reworked the Yellow Dragon to breathe either a line of acid or a cloud of poison. It is immune to acid and poison damage, and it is vulnerable to thunder and force damage. There are other changes too – no flying speed as it has no wings; +10′ to base burrowing speed; higher Constitution; swap scores for Intelligence and Wisdom, all justified by the general idea of the element of Earth and how it is understood.
Figuring this out took a lot of work, but I’m proud of the result.