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"Twilight Sparkle! In our time, we were the spark that gave the Element of Magic life. We were the protector as our sister was love and guidance. Though we regret that it must fall on such young shoulders, this must be thy duty now. Our heavens are now thine. Guard our subjects well! Have at thee, chaos! Ubi concordia, ibi victoria!"

This was inspired largely by this song: http://www.youtube.com/watch?v=6gilH6f2hHk Because it has a really powerful 'ancient forces battling' feel for me. If Celestia and Luna ever really got serious about a fight, I feel like this song would be entirely appropriate.

She's transformed back into a larger, Nightmare Moon-sized form for battle. I imagine the platform she's standing on is actually some kind of gigantic floating clock face or sundial, too.

That reflection took longer than the actual body. Trying to be exact is what takes up most of the time I put into a picture; I'm really glad programs have guidelines and rulers now.