Water, Fire, Grass, Light, Dark, and Neutral. These are the main six elements that formed six beautiful planets to form the universe. However, before this peace, there was a lack of balance. Centuries prior, Water, Fire, and Grass were trying to stop the war between Light and Dark, but they couldn't do it alone. Upon searching for some sort of extra ally or help they found the Neutral Element. The Neutral just existed with no purpose, unlike the others. It was as if the Neutral was born out of midair. The three decide to let the Neutral join them after seeing what they're capable of.
With the help of the Neutral, they ended the war between Light and Dark. With the elements in peace with one another, there was a peaceful universe for the next 500 centuries. As time went on the elements had descendants, ones they look over in spirit. Two different kinds of descendants. One descendant is called Elementals. Elementals use powers based on the element they're born in. The second type is an Elementan, they're basically the civilians of each element and their 'power' is too small and weak to use for combat.
The universe is set with six different worlds, obviously for each of the different elements. To make transport to other worlds easy all the worlds are gathered in a circle, in the center of the circle, very far below the worlds is a black hole. No one knows where it goes to or it's origins. They're in a circle where Fire is where it begins and Dark is where it ends. Fire, Water, Grass, Neutral, Light, and Dark. That is the order of the worlds in their circle.
Elementals host a special ability to switch between forms. They would have three forms, the first form is their normal form and they use energy at a 1x rate. In the second form, they will have appearance changes which could lead to slight differences in how they fight, but their moves will most likely be the same yet stronger with energy being drained at a 2x rate. The third form has the biggest and most obvious difference with their element obvious, they'll have a few moves that are powerful and use energy rate at a 3x rate. They need stamina and energy to use their elemental power, if they run out of energy they'll faint, if they fight their opposing element they'll need to use more stamina to do actual damage.