Earth, Water, Air, Fire. All four are the top elements of the universe. So at the discovery of Sea stone, there was little thought onto the concept that there may be other stones similar to it. But that way of thinking was blown out of the thought of only myth when three stones began to show up with similar properties as Sea stone, and the ability to nullify the effects it holds.The stones come from their respective spots on the planet. The Fire stone, held by Whitebeard, was found after a dormant volcano had erupted once more.