Primary Elements






Secondary Elements


Tertiary Elements

Legendary Elements

Other

Ideas
When I started theorycrafting the game's systems, I debated having a different kind of elemental system rather than using the traditional "generic" elements. I came to the conclusion, however, that it's not the elements themselves that matter, but how they are used as game mechanics. Each of the elements in the game will have specific conditions that will enhance or diminish their effect.
For example, let's take the following battle situation:
Now what should happen? Well, since it's raining, the Pyra(Near a river bed, two units are currently engaged. The weather is overcast with some light rain. Unit A is currently standing in shallow water. Unit B, who is standing on solid land nearby, decides to cast a Pyra() elemental spell at Unit A.

So what did the caster, Unit B learn here? That being waist-deep in water is over-powered? Exactly! Er, wait, Unit B learned that when elements are involved, you have to take into account the weather and terrain. This is on top of the target unit's actual elemental resistances.
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Now, Unit A might be pretty proud of herself. Nearly nullifying an attack spell from one of the most offensively inclined elements, Pyra(

However, let's hope she checked the current position of Unit B's ally, Unit C, a certain Magus by the name of McThunder who is very good with Vola(

One weak thunderbolt from Unit C and she might be floating in that river. Both the weather and the terrain favor Vola(

More Ideas
While elemental systems are a primary feature in many RPGs, I've always really seen them as a great place for lore. Whether it's the Magick user who mastered the ultimate Pyra (fire) magick or the story of an entire clan of Gala(wind) magick users who lived in isolation for 300 years, it creates a neat structure for the world around it. This falls more under Story/Lore so I'll save it for another post.