Zigofir: a Elemental journey

In the world Zigofir everybody has a Elemental power, water, fire, earth, or air. Each element has its own kingdom with their city's. In each kingdom there is 4 crystals of the element that the kingdom is, if all 4 are acquired you can summon the God of that kingdom but if you get all 16 it will summon a demon of all elements and if you defeat it you will possess a power not known to humanity..