There are five elements in Puzzle Breakers: Fire, Nature, Ice, Light, and Darkness. These elements are more than just the runes you match to deal damage/fill mana; they are associated with strengths and weaknesses for every hero in the game, as well as the various enemies and war mechanisms that you encounter throughout your journey.
This, in a sense, is what makes Puzzle Breakers a unique Match-3 game with RPG and strategy. The elements all have strengths and weaknesses to one another, in a cycle of "rock-paper-scissors:"
Fire is stronger against Nature,
Nature is stronger against Ice, and
Ice is stronger against Fire.
The two other elements, Light and Darkness, are both strengths against one another, but deal weak damage against their own Element. Talk about "mutually-assured destruction."