@Background Pony #A6A3  
Or since it’s a mlp doctor who comic, she is a Zygon

This page is quite interesting if you’re not obsessed with the “Twilight is an evil villain” explanation. It makes me wonder if Twilight is fully aware of everything that’s going on outside the castle walls. She might be aware that there are rebels and maybe a few other things, but many of the things that led to the rebellion as well as the specifics of fighting it might be under the control of somepony else and she has trusted them too much.
 
I’m still going with my original theory of her losing her way and the rest of the mane 6 re-teaching her the magic of friendship and her redeeming herself through death.

“Yes, we’re all deathly afraid that you’ve become triple the psycho we once knew.”

Rarity, you maaay want to simply go without talking this time around.

@Tetrominon  
Yes it is.
 
She is not a changeling. She is just a very, very twisted version of Twilight that want to murther them to live forever. Maybe.

“We heard you’re a changeling.”
 
Also, is that a sonic screwdriver in the Doctor’s mouth back there?