Fallout: Equestria

Or even if scourge from sonic won the war and created a nuclear bomb and turned equestria into nothing but dust

Probably a full scale nuclear war or thanos destroying the whole universe

@Scrounge
You mean this is what would have happened if Midnight Sparkle succeeded? Drain all magic of the Rainbooms and all of Equestria and possibly grown giant like Tirek and as what we saw towards the end of Legend of Everfree, wipe out all life in both worlds, overthrew the Alicorn princesses, conquer both worlds and upset the balance of both worlds creating havoc?!

@Background Pony #9B62
The Storm King wasn’t introduced until the movie in 2017.

Also, there is something else

@Background Pony #9B62  
What about the Tantabus. He appeared in season 5 before this point

@Background Pony #9B62  
Well it wasn’t the Storm King Timeline. You just made that. It was some unknown apocalypse that cause destruction and extinction to all life in Equestria.

The seventh timeline went to a villain who wasn’t even in the show until after the events of season 5. It can’t be the pony of shadows (would not’ve been released if it wasn’t for twilight) or cozy glow (would’ve never became evil without attending twilight’s school and learning about tirek).
 
The Storm King wins.

@Phantom Rider  

It’s simple:
 

maybe, maaaybe that’s the future where cozy, tirek and chrysalis win in s9 ending…

@Detsella Morningdew  
Yeah, I’d forgotten about that as well until I re-watched Season 5 last week. So you’d be forgiven for forgetting. With that in mind, I could only really see three possible causes for the Ashlands timeline. I’ve been over Starlight a few times by now, so I won’t really go into detail about her again. I could also see Daybreaker appearing if Celestia went overboard in fighting villains in the absence of the elements. Last one I could see would be those blunderseeds that Discord planted that would’ve drained all the magic from the tree of harmony, but I don’t think that’s it either because that would fall under the Discord timeline where at least some magic still works.
 
So really, the only one that makes sense to me, considering what we can gather based on both in-universe and out-of-universe (behind the scenes) reasons, is Starlight.

@Dark Dash  
Right! Haven’t watched the episode in a while, so I kinda missed that fact. No matter what happened in the timeline plot-wise, it’s always the same in exact time measurements.

@Detsella Morningdew  
There is also the fact that we only see where those worlds are by the time of the Season 5 Finale (Remember that Twilight mentions that they are in “the present” after Starlight changes time, not the future). So by the time the Wasteland timeline exists, it would be long before Grogar’s return. Even if he did return, there’d be nothing left by the time he did, and since he wants to rule Equestria, his goals wouldn’t matter. After all, what good is it to rule over a dead world?

@Dark Dash  
You make extremely good points. While I originally had thought of Grogar for his role in the origins of all the monsters we see, a world ruled by monsters might not necessarily destroy itself. Just become a society of monsters. And he is significantly more self-aware of mistakes than other villains we have seen.
 
But all these realities make a lot less sense when we realize that Grogar’s escape was inevitable rather than caused by one of the Six. He seems significantly more powerful and cunning than anybody but Discord.
 
Still, Starlight really is the one I could see causing this, especially if she takes Celestia and Luna’s cutie marks, and no other unicorns can take up the task of raising the sun and moon.

@rylasasin  
That’s true. I’m just saying that, of the villains we’ve been shown (real or not), Daybreaker is the only one I could see willingly leveling the entire world. Sombra wanted world domination, Nightmare Moon wanted her night to be eternal, Tirek and Grogar just wanted power, Chrysalis needed to feed herself and her hive, Discord wanted to bring about everlasting chaos, Starlight wanted to bring about Equality for all, the Pony of Shadows just preyed on the weaknesses of those it attached itself to, and Cozy Glow was pretty much horrifically misguided in her desire for friendships.
 
Chrysalis and the Pony of Shadows literally need others to feed off of. Sombra, Tirek, Nightmare Moon, and Grogar presumably want to rule over Equestria and other lands, not annihilate them. Discord wouldn’t have any fun if everyone was gone, and Cozy Glow’s goal would be a moot point if everyone else is dead.
 
Daybreaker isn’t concerned with power, ideals, or friendships. Just doing whatever she wants and destroying anything that gets in her way.
 
So she’s the only one who’d willingly destroy things in such a way, but at the same time she isn’t actually real (as far as we know.) Starlight is still the only one that’s real that I can think of whose actions would lead to the end of the world since everything would eventually just waste away into nothingness that could’ve feasibly happened. As Detsella mentioned below, Cozy Glow’s actions would’ve never happened without Twilight becoming the Princess of Friendship.

@Dark Dash  
Daybreaker however is Starlight‘s nightmare, not Celestia’s, so she hasn’t even been proven to exist.

@Detsella Morningdew  
I’m not entirely convinced of that. The reason being that Grogar doesn’t want to destroy Equestria or deprive it of its wealth or magic. Grogar’s sole aim is the attainment of power. One could argue that his actions, and the inevitable conflicts with other villains, would lead to this reality, but I don’t think that’s the case. The only villains I could see accomplishing such a world would be Starlight or Daybreaker. The former would’ve hated cutie marks regardless of Twilight meeting her friends or not, and the latter was entirely focused on destroying anything that stood in the way of taking what she wanted. Starlight’s future would lead to everything wasting away since no one would have their unique talents that allowed them to do necessary tasks, while Daybreaker’s future would probably see her leveling any cities or towns that questioned her.

I’m saying it now - Grogar.
 
For those saying Cozy Glow - she wouldn’t have really existed without Twilight being the Princess of Friendship to begin with.

Everything’s destroyed.

@Background Pony #380D  
I don’t think this what a Midnight Sparkle timeline would look like. I think that would actually be even worse than this. At least the landscape itself is relatively intact, rather than being ripped apart by portals between worlds. If Midnight Sparkle were left unchecked, I have no doubt she’d make swiss cheese of that timeline’s multiverse in short order as she took apart reality itself just to see what made it tick.

I’ve always taken this to be the Starlight timeline. One fan-fiction described this pretty accurately (I can’t remember it off the top of my head), where when Starlight had succeeded in taking away everyone’s cutie mark, nothing could be done. Farmer ponies lacked the basic skills to grow food, what meager food was harvested was rendered inedible by chefs who couldn’t cook. Weather ponies couldn’t stop storms and catastrophes without their talents and places that were destroyed could never be rebuilt as no one had the skills to do so. So everything just wasted away into nothingness.
 
That said, I do also think the comments about this being the Daybreaker timeline are a good theory. Especially if we’re referring to this as he “Ashlands Timeline”, where I’d be inclined to believe this is the result of the world of Equestria being incinerated by an evil version of Celestia. Nightmare Moon never seemed to truly have any goals outside of the S5 Finale alternate timeline; she mostly seemed hellbent on taking revenge on Celestia and Equestria itself.
 
If we assume Daybreaker to be a Celestia who grew tired of putting up with all the villains and conflicts, then it’s entirely possible she simply burned everything until there was nothing left but the ashen remains of what was once known as Equestria.

This has probably already been said but I don’t feel like going through the comments to check. This is Cozy Glow’s timeline.