Looking at Evillestia’s cutiemark.  
Can we tag her Blackhole sun.

@Background Pony #A242  
The way I figured, if most of the beings in this world were reversed, possibly the nightmare forces could be as well.  
Maybe Mirror-Luna acts as their jailor keeping them on the moon, but over time they could have some sort of influence on her.  
So she rebels against her sister who traps her there, 1000 years pass Mirror-Luna tries her coup a second time but Mirror-Celestia had her evil mane six corrupt for permanently.

@Background Pony #00B9  
how would that work? if this is a tainted luna already, how does she become possessed?
 
and don’t say it would be good nightmarem oon. nightmare moon is luna demonically possessed. a good variant could not jut posses beings.

@Background Pony #CA14  
Maybe Starswirl or Sombra? Or a combination of Sombra and Celestia?

@Background Pony #CA14  
It’ll be Celestia’s ex-boyfriend: mirrorverse Sombra.

Black Sun and Shadow Moon.
 
or in evil!luna’s case red moon ala Moons Eye Plan/ Infinite Tsukiyomi.

“It will take an unexpected sacrifice to save day… but from whom?”  
100% it will be Celestia since it was somewhere mentioned that this arc as suppose to be somehow focused on her  
but if it’s not her then who? Spike? unless new unknown ally will appear in 2 or 3 part of this story and he/she will “sacrifice”

Fighting your evil counterpart? Don’t forget to use Din’s Fire and the Megaton hammer.

@JP  
So suddenly getting defeted one time is a “lot”?
 
 
And honestly knowing how Luna just sleeps during a crisis, her evil twin will just sleep through all this.

Celestia VS. Eclipsetia

@Hypastpist
 
Maaaaaaybe because Tyrantlestia is already massively tread water already. Can’t expect the fandom to jump at the chance for something which essentially has been seen before

I vote for this to be the featured image.

Evil Celestia needs a goatee.

@Background Pony #CA14  
oh yesssss

i was right about evil Celestia’s cutiemark. I’m fucking genius.

@JP
 
I dunno. IDW actually makes Celestia pretty bad ass most of the time.

serious catfight is serious… specially Luna and her cat pose
 
@Hypastpist  
I give it like less then a week and there will be nsfw version of this cover with royal foursome.

why havent we had EVIL!celly clop yet?
 
its been awhile
 
fandom im disappoint

I hope they at least show us the mirror universe’s Nightmare Moon.

Dem boots tho

@JP  
Calling themselves the War Moons: Phobos and Deimos.

Knowing how often Celestia gets her butt kicked (sorry), they both knock each other out at the same time and end up lying on the ground, unconscious.
 
Meanwhile, in the background, the two Lunas fight and destroy half of the castle (or wherever they’re in) until hours later they realize how fun it is to blow up stuff. They then team up and go chase their common enemies as an unstoppable team.

Man, this looks great! Can’t wait to see the inside of it! I love the little touches of difference, like with the eyelashes and the two-pronged crowns.