Hullo. This is the artist.  
Plezzzz allow this comic to burn in hell.

Twilight: …Wait, Nightmare Moon already tried that. *jewelry reassembles and cue taste the rainbow*

Aw Sunset Nightmare Moon called she wants her plan back of destroying the elements

@Vaidelot  
@Background Human  
This probably won’t happen unless they’re suddenly transported one season’s worth of in-show time into the future, but Rainbow Power is powered by the Elements using the tree and/or box as a conduit. Even then, once they got Rainbow Power in S04E26, it’d seem as if they either focus their energy on the elements in the tree no matter where the mane six are in the world or it’s activated using their own internal magic and that the energy of the elements was given by the elements themselves and/or tree and/or box.
 
tl;dr: The Chaos Emeralds in Sonic Adventure or whatever the hell revived Harry Potter after Voldemort killed him. :3

@Mildgyth  
That’s alright. I made sure to add the tags just now

@Mellow91
 
I forgot about adding that part on the tags.

What some people here (including mildgyth apparently) don’t seem to be realizing is that this is not merely “Nightmare Sunset”; this is actually Princess Celestia possessed by Sunset Shimmer, and that possession triggered a transformation that turned Celestia into Nightmare Sunset!
 
Sounds bizarre, I know, but that’s pretty much what’s going on. I added the “possessed” tag.  
Mildgyth, if you’re seeing this, please remember to add that tag to this version of Sunset/Celestia’s next page appearance!

@Vaidelot  
My thoughts exactly.

@Vaidelot
 
“I’ve ground them into smaller fragments! it won’t fail this time!”

You’d think the destruction of such powerful artifacts would be more catastrophic.
 
Then again, it’d be a bit anticlimactic to have everypony die in a big fiery ball (that was visible from space).

Well, congratulations with making the same mistake Nightmare Moon did…