So one day, Tory got the bright idea to wear two shirts at the same time.
That's it. That's why she looks a little like the twins from Big Fish. (More precisely, I wanted to be able to show artists a picture and have them not copy the color of her shirt. Note to self: get hex codes for her colors.)
Oh, afterthought: she still has one personality and consciousness. Also, she's not technically a shapeshifter, but that's not really any impediment to shifting shape.