Past Sins/Awesome

• The CMC sneaking into Nightmare Nyx's castle. Three little fillies sneaking into a heavily guarded castle is not something you see everyday, folks. CUTIE MARK CRUSADERS SOLID SNAKE! YAY!!!
  • Pinkie Pie's sheer audacity in sneaking into Nightmare Moon's castle just to deliver a birthday party invitation qualifies too. The guards seem to have suffered a drastic drop in efficiency once Spell Nexus hit them with the essence of Nightmare Moon.
    • Well, this is Pinkie Pie we're talking about. Remember what happens when you talk about Pinkie Pie Promises?
      • FOR-EVERRRRRR! *Sinks back down into the comments, holding a sponge and apple*
• Nyx/Nightmare Moon's taking down first the entire Royal Guard all by herself should qualify her as a One Mare Army, and then defeating both Celestia and Luna in straight-up fights.
  • In context, though, it was also a bit of a tearjerker...
• Nyx saving Twilight from Nexus trying to hang her. And, by extension, when Nexus inevitably gets the ever-loving shit beaten out of him for what he did to her.
  • The expected pummeling did not happen. What did happen was far more calm, rational, and awesome. She demolished the huge cloud of the original Nightmare Moon's essence that had corrupted Spell Nexus and then proceeded to free the others from the portions of it that they had been corrupted with.
    • Spell Nexus sealing the Corruption inside himself before it could spread of its own volition. That took serious guts from a pony that Neighs Like A Little Filly.
• Nightmare Moon versus every monster in Everfree. Even factoring in Me's a Crowd, that was epic.
  • On that note, Fluttershy stepping in and using The Stare on the Lupus Minors to send them running.
  • From the same fight, Pinkie Pie rigs decoys of herself filled with knockout gas to take out some monsters. They fool Nightmare Moon as well.
  • Cherilee shows her Badass Teacher credentials by attempting a You Shall Not Pass to protect her students. Nightmare Moon bails her out with a Dynamic Entry.
  • Applejack uses her rodeo skills to slow down a Lupus Minor.
  • The final boss is a Lupus Major. Remember the Ursa Major from Boast Busters? This is the wolf version of that, and like the Lupus Minors it's actively hostile. Nightmare Moon sends it running with a single lightning blast, visible all the way from her castle. The Lupus Major gets it's own Coma for almost killing Nightmare Moon in the process.
• Twilight Sparkle vs Diamond Tiara's Father, maybe not a major CMOA, but still, it does belong on this list.
• The speech Nyx delivers when submitting herself to the Royal Pony Sisters is pure badass. Even the universe agrees, because it's later revealed that she earned her cutie mark just afterward.

Nyx: As an alicorn, I can bear the burdens no other pony can. I threw myself in the way of a Lupus Major to protect Twilight because, while the beast wounded me, it could have easily killed Twilight. The pain I endured saved not just one life but lives all over Ponyville. It's far better for me to be wounded if it means somepony, anypony, can continue to live and be happy. I can be bruised, battered and beaten but, as long as there is still breath in my lungs, I will continue to protect ponies. I will protect them, because what can kill them I can survive, because what hurts them is but a scratch for me, because it's the one thing I've been able to do right.

• Chapter 21 shows just how unstoppable Twilight's rage can get when she rage shifts and starts trying to beat down her physical god mentor with pieces of a castle!
• A meta one; but this troper feels that the Authors themselves deserve to be mentioned here; for taking the redeem Nightmare Moon plot line and doing it in such a way that it's actually believable.
  • Another meta one, but just the fact that Pen Stroke is allowing the original edit of this story to be riffed says something. More details are here (near the bottom).