This image is based on my personal headcandy on the physicallity of the princesses and why Luna(sometimes), Twilight and Cadance are not physically just like Celestia. The theory is that, in short, the mane and body represents and embodies thier power. I'll clarify in the comments with what I belive is evidence to support my claim. Only if interest is shown. #TwiglightSparkle #Princess #Pony #Eyeglow #Headcannon #Theory #MlpFim