This is pretty old. It was drawn in about 2months ago. I didn't upload it because I tried to evade writing the description.
This was drawn because I came up an idea, dividing the elements of harmony into two sides, and as cliché, they are the sun and the moon. Originally, I just separated them according to their coat colour: warm and cold. But then, I thank it would be better to have all the three races of pony in each side, so I switched the position of twilight and pinkie. Instead, I tried to give twilight a brighter colour outfit, but it's quite difficult.
I just place them into some common RPG roles:
applejack and rainbow: warriors;
twilight and pinkie: magicians;
fluttershy and rarity: healers...
Mmm...something like that...