I’m still determined to say Luna’s right in this and Nightmare’s not as capable against all these implied villains as she arrogantly believes.

She’s powerful enough to modify millions of ponies’ circadian rhythms

I think there is a limit to alicorn magic.

It makes it likely, but doesn’t prove it. We wouldn’t have much of a story if nothing comes of that though.

It’s been 1000 years since she brought eternal night. If any sort of ecological disaster was going to happen, it would have occurred already. And Equestria still has daytime, so it mostly seems to have only involved switching the sleep schedule of ponies.

Who sentenced Tirek to Tartarus is not explained, but it doesn’t disprove that Celestia won’t kill others. We also still don’t know how shattering the statue would affect Discord, if at all.

Who the ‘true’ ruler of Equestria should be is vague without knowledge of what sort of government Equestria is, but if you accept the commonly held belief it is a diarchy of princesses, Celestia by herself is not the ‘true’ ruler. Nightmare Moon, being an alter ego of Luna, has as much of a claim to that title.

That raises the question: does Nightmare Moon have Luna’s memories? Because if she hasn’t, you cannot blame her for being ignorant of events she has no knowledge of and thus cannot prepare for. If Luna is able to communicate at all with her Nightmare self, it still wouldn’t help either; Luna is too deeply invested in returning her sister and casting Nightmare out for her to believe anything she tells her.

Even if Nightmare Moon is fully cognizant of these past events, there is no reason for her to prepare for anything. Celestia didn’t, and she only reacted to the return of her past enemies. She didn’t know Discord would break free once the Elements were attuned to the Mane Six (and they’ve not been connected to her for a 1000 years in this story so his release now is even more of a mystery). The Crystal Empire’s return was also unexpected for Celestia. And the only warning Celestia had for Tirek was a prophetic dream. It seems rather insincere to blame Nightmare Moon of being an evil ruler for not being omniscient especially since her goodly sister isn’t either.

That doesn’t mean anything when their prey are adapted to have night vision. In fact, Nightmare Moon’s guards receive a transformation into a batpony, so they may actually have better hearing than the regular royal guard under Celestia. Nighttime raids are the worst time to pick for changelings if they want to capture ponies unaware.

We’ve only seen Chrysalis match an alicorn princess under special circumstances, one being after draining Shining Armour’s love of Cadance, which can’t happen here. Even if we generously assumed Nightmare Moon to be as weak as Celestia, it would be a very one-sided fight for Nightmare Moon. However Chrysalis is meant to be introduced into the story, I doubt she’s going to fight Nightmare Moon on her terms.

Nightmare Moon possesses Luna, or IS Luna. And her not killing Celestia doesn’t seem to be because she’s incapable, but because a more cruel, ironic punishment in the form of banishment to the moon presented itself (conform with the timeline from “The Cutie Re-Mark”). In “Princess Twilight Sparkle” Celestia was losing that fight until she used the Elements, and her absence during “Friendship Is Magic” implies further she cannot stand up to Nightmare Moon.

From Nightmare Moon’s perspective, Celestia was the usurper. And so far she has been shown as stern and having some skeletons in her closet, but her subjects’ utter loyalty actually has allowed her to be benevolent. She has had a sexual relationship with Twilight Velvet and is not the clingy, jealous type of ruler who abuses her power to prevent her marriage to Night Light. Even taking on her daughter and projecting her desires onto her (which Twilight seems to be willing to reciprocate). Twilight also did not think Mrs. Cake falling behind schedule was serious. So when things go her way, Nightmare Moon can be good.

Of course, when things start to go wrong she will no doubt react more harshly. That Nurture arguement has held true for many rulers. But that is what has seperated the beloved monarchs from the loathsome tyrants throughout history. And Nightmare Moon’s track record over a 1000 years appears good enough that ponies adored her.

Just because it’s a different timeline doesn’t mean that he’s incapable of coming back. The fact that Luna seems to have foreseen this proves it.

If Nightmare Moon was all about compensating, then she wouldn’t have needed to forcefully bring about Eternal Night to begin with. just because they don’t seem to have taken place yet doesn’t mean that the absolutely won’t.

Thank you for proving my point, all they need was enough matter to overpower her and Equestria is suddenly Under New Management.

Celestia was willing to banish Tirek to Tartarus for a thousand years just for threatening her subjects, if she have the chance to Shadow Discord statue without any drawbacks I’m pretty sure if she would have. the fact that it probably would have freed him again was the only reason she didn’t.

She took advantage of a princess in her moment of weakness, forcefully usurped the throne, and has been keeping their true ruler sealed away just so she can have the entire Kingdom all to herself, not because of what she thinks is best for her subjects, but what she thinks is best for her. Because she’s selfish.

The fact that Luna has to warn someone else because the one possessing her is too arrogant and prideful to prepare for such threats says a lot. Sorry, but there is no benevolence in her. The only reason she seen as benevolent by anyone is because she’s good at hiding her tyrannical side.

No, it wouldn’t be that obvious because they be doing it under the cover of darkness.

Considering the fact that she’d have more than enough love drained to match Nightmare herself, it wouldn’t exactly be hard.

Considering the fact that the blizzard was only there because the Crystal Heart wasn’t in its rightful place, I think it’s safe to assume that Sombra would keep it hidden so the blizzard would continue and therefore make it harder for Nightmare and her Army to Traverse the Frozen North.

Considering the fact that all nightmares blast did was done her temporarily, I think it’s pretty fair to compare their power. Considering the fact that even ticking into account that she had possessed the princess, she still couldn’t actually kill her.

Nightmare hasn’t become benevolent over the years, she’s just become better at hiding it so that she can get more subjects on her side. She still a usurper, still a tyrant, and still isn’t the rightful ruler of Equestria, no matter what timeline she’s in.

This isn’t based on “The Cutie Re-Mark”, but on what Equestria is like if Nightmare Moon had triumphed over Celestia 1000 years ago, taking inspiration from the Nightmare Moon timeline in “The Cutie Re-Mark” and Twilight’s visions in “Princess Twilight Sparkle”. Discord is still a statue, and probably not on display in the Canterlot Gardens where three stupid fillies can re-energize him with their petty squables. Though Luna thinks he will return. Somehow.

Such ecological disasters don’t seem to happen in Equestria, and with the world having adapted to eternal night pretty well under Nightmare Moon, it seems to be pretty resilient. Also, if she can force the environment to conform to her vision for the world, I’m pretty sure Nightmare Moon can compensate or reverse the effects of the day. You know, as long as Discord isn’t mucking about. Who is responsible for his own chaos in any timeline or alternate universe.

Both these villains needed alicorn magic from the royal sisters and only the Storm King even did some fooling around with it before he was unceremoniously defeated. Without Celestia, they’re already lacking one alicorn. But if they were in a position to drain Nightmare Moon, they no longer would need to mess with the sun.

What makes you think shattering him isn’t an option? Celestia may have vetoed that option at the time, but Nightmare Moon would have had no such compunction. Luna’s belief he will return suggests she either didn’t bother to, or it is ineffective though.

Nightmare Moon did actually use the Elements to banish Celestia, so she can control them somewhat. But she appears to suffer backlash from them, perhaps allowing Luna to regain a limited measure of control in her weaker moments. If so, all the more reason to encourage Nightmare Moon to keep using them so she’ll lean more towards being a benevolent tyrant.

As kidnapping ponies under Nightmare Moon would be as obvious as doing so by daylight under Celestia, this seems unlikely to be the case. And with no Canterlot Wedding, I don’t know how Chrysalis is supposed to carry out an infiltration.

Actually, we only know that Celestia and Luna dealt with him together, not that he was strong enough to require their combined power. And the blizzard only threatened the Crystal Empire because Flurry Heart destroyed it, who will thankfully never be born in this timeline.

Celestia used the Elements of Harmony and failed in this timeline because Nightmare Moon dodged their blast. She was not holding back, she’s just a weak fighter (I think we have to start accepting that after all the times she’s been beaten). Trying to gauge Nightmare Moon’s power by comparing her to Celestia is not all that helpfull.

Agreed, not to mention the fact that there’s also little to no evidence of Nightmare being as benevolent towards her subjects as she is to Twilight, or the fact that even if she was able to somehow use her magic to make Equestria adapt to a permanent night, Nightmare Moon has essentially doomed Equestria since raising the sun would probably kill off/weaken most of the population.

Think about it, suppose Discord gets free and decides to “shed a little light” on Equestria for shits and giggles? And before you say she probably dealt with him, you need to remember that her timeline came in before Discord’s, so by this logic not only is Discord still out there, but in his own time when he successfully defeated her.

Then there’s the fact that the ecological system would suddenly go nuts and everything would start dying off, why? Because they haven’t adapted to the sun in years due to Nightmare forcing the world to adapt to a night only environment, an issue that they wouldn’t have to deal with if Nightmare hadn’t brought about Eternal Night and forced them to adapt to that said lifestyle.

Hell, it’s confirmed that unicorns were able to raise the sun themselves in the past before the sisters came along, who’s to say that other powerful entities such as the Storm King or Tirek (both of whom have powerful magic, or at the very least enough to rival the Royal Sisters) won’t simply raise the sun to weaken the inhabitants and then easily conquer them?

Discord:
Considering the fact that shattering his statue is not an option since that would just free him again (and if it were that easy they would have done it a long time ago), and NM sure as hell doesn’t have the elements on her side since they disconnected themselves from her and Celestia after their fight, it’s more than likely that he hasn’t feed himself yet but eventually will…. and NM ain’t gonna be a match for him with the Elements.

Queen Chrysalis:
I doubt Cadence would have had her wedding since she’d probably be locked away or on the run due to her connection to Celestia herself, so no Chrysalis wedding plot. And the Queen would probably be on the down low and would be perfectly fine with simply kidnapping innocent civilians for the Hive to drain since it’d be easier for them to abduct civilians in the shadows of the night, which is eternal. So it’s possible that she’s actually an even bigger threat then when Celestia was in control.

King Sombra:
It took both Celestia and Luna to deal with him, and that’s not even getting into the horrible blizzard surrounding said Empire that both of them couldn’t push back.

Nightmare is strong, but she isn’t that high on the power scale since the only way she was able to blindside Celestia was because she was holding back since she was fighting against her sister, this is more than likely why she was able to seal her away in thit timeline. So it’s too big and assumption to say that she somehow beat someone who could only be defeated by said elements.

@mjangelvortex
This is a good thing that is coming to an end before it even got to start and for something far less interesting.