Bloody Marie will probably be unlocked after you complete like, storymode, or something.
But yeah, Double 'copies' moves from other characters, but are actually not used by the characters themselves. Like Arms said, they're scrapped moves that they couldn't fit on the original characters in time, which is probably why Double was the last person announced.
I still wonder why her name is just, Double.
Why not something more interesting, and what I assumed to be: Double Trouble :I
EDIT: by the way, is there any art of Brain Drain?
Guess whose Ms.Fortune Tee shirt arrived in the mail today! This lucky feline's!
It looks pretty rad and if I can get pictures I will show them!
It looks really great to say the least and shipping was done pretty quick, though price makes me say think carefully before ordering anything.
Everything about Double is fairly messed up, and admittedly I love mimic characters in every game I've ever played and she is no exception. She is so going into my list of characters to play as much as I can, and pretty much solidified me buying this as soon as possible.
On the list of character's that are mimics, Double does it very well.
A lot of double's just use the exact same data and posing and weapons for their move-set, whilst Double has the moves slightly modified stuff and not to mention various moves that have not been seen. I look very much forward to her supers.
The mane 6 of My Little Pony, with access to the elements of harmony? Or Derpy Hooves, having accidentally stolen the skull heart from Bloody Mairie after she was defeated, and it corrupted her in it's entirety turning her into a SKULLPONY? More importantly, if they mane 6 do win, is Derpy un-corrupted? What if instead of Derpy, it was princess luna?