@Dirty Bit  
Yeah, I imagine their siren forms were many times more powerful than the manifestations of them that the Dazzlings were able to summon in Rainbow Rocks. Hence, why Starswirl had to banish them to Earth (or Human Equestria, whichever you prefer it to be called).
 
Also, agreed. We’ll need that giant unicorn instead of the rainbows, in order for it to be cool.

@Chinigan O’ Donovan
 
An interesting theory…Especially given the amount of power needed to defeat the Dazzlings.
 
I mean honestly, that giant alicorn apparition was loads better than the Rainbow Power used to defeat Tirek.

@HighRollerHydra  
We know that Starswirl was a brilliant unicorn wizard, who yes, was not very good at making friends. He was probably book smart, but had little ability to form lasting and meaningful bonds with other ponies.
 
Based on the stories of him so far from the show itself, he was probably a sentinel of some kind for Equestria, protecting it from threats such as Tirek and the Sirens. He likely did what the Mane Six do now all the time, which is fight antagonistic forces in general.
 
 
@Dirty Bit  
I have a theory, which is that Starswirl was not able to contain their power long enough or in an effective way that could allow him to imprison them in Tartarus. Perhaps they were so powerful that Tartarus was not an appropriate prison anyways, or they could easily escape if locked away there.
 
Another explanation could be that their crimes were so atrocious that he had to banish them from Equestria completely, using some kind of space bridge or portal to send them away, trapping them in another world. He sent them to a world “without magic” as we were told, assuming that they’d never (1) regain the power they needed to use their magic or (2) be able to return to Equestria. For all we know it was a desperate move, and the best option he had at the time.

@HighRollerHydra
 
Both Celestia and Twilight have outright stated that Starswirl pretty much invented what they consider “modern magic”. Celestia also stated that Starswirl used frienship magic to turn Skorpan against Tyrek. So he was probably pretty smart and knew a fair bit about friendship, and just had really sucky options for friends, so he couldn’t learn about it with the depth that Twilight had.

@HighRollerHydra
 
I think it was implied at the Season 3 finale. Whatever the case, at least we got a decent movie out of it XD

@Dirty Bit  
Didn’t Celestia imply that Star Swirled wasn’t that smart? Didn’t understand friendship, or something like that?

@Somber Star
 
Well, we can’t expect these sirens to wallow in the depths of Tartarus, can’t we?
 
…Then again, it was Starswirl who banished them, so maybe it didn’t come to mind. Either that, or the sirens weren’t as dangerous as Tirek.

@Dirty Bit
 
FiM’s human world is, I imagine, only as much like our world as a sea horse is like a horse.

@HighRollerHydra
 
In their defense, our world kinda sucks XD

They really need to stop making the human world a dumping ground for villains.

@Red-Supernova
 
That kind of just means that Sunset was more typical of ponies from Canterlot than Twilight. Also, it does beg the question of how many “favorite students” Princess Celestia has gone through over the centuries, since Sunset and Twilight are at most a few years apart. By extension, it also raises the questions of how they handled the pressure and what happened when they failed (since there’s only one known success).

@Somber Star  
Judging on how I view the Changelings and the Dazzlings, they’ll eventually understand friendship in due time.
 
I did mean to say “can’t be gained by force.” I corrected myself in an earlier post.  
Well, I have some theories on why they want to be loved but its pretty much fanon, for now.
 
Hmm, interesting theory. However, I still stand by my headcanon.
 
Yeah, but Twilight was more socially awkward than arrogant like Sunset.

@Red-Supernova  

 
Yes, they are. And that’s why I believe that their lives are going to be miserable in ways that do not promote the harmony the show is all about. The ponies did not introduce either faction to their way of thinking, but rather defeated them in the traditional manner, perhaps dooming them in the process.
 

 
I think you meant to say ‘can’t be gained by force’, and in any case, I’m still confused on their intent to be liked in the first place. Animosity is the source of their power and food. Reason would dictate that that would also apply if it was directed at them.
 

 
I think it’s both, like with the Changelings. Where creatures in our world just become fat and lethargic if they eat too much, it seems those native to Equestria gain power and go crazy.
 

 
To be fair to Sunset, so did Twilight, except I don’t think she even suspected the alicorn thing and was just obsessed with study for its own sake. I think Twilight’s life would have been pretty sad if she hadn’t been sent to Ponyville, since she had no ambition but the intellectual capacity and academic drive to probably end up holding several doctorates in a world where they’re not really necessary.

@Red-Supernova  
Happens to all of us. I just was confused by what you meant, so I was trying to help you out. Thanks, Red-Supernova.

@SuperSonic15  
I meant to say “they have to learn that respect CAN’T be given by force”.
 
I made a grammar typo.

@Red-Supernova  
Don’t you mean earn it, not learn that it can be given by force?

@QuasarNova  
Yeah, only to end up meeting the same defeat via the Magic of Friendship.
 
And can we end this discussion now before we add any more comments than we need to?

@SuperSonic15  
Exactly.
 
@SuperSonic15  
Yes. The Dazzlings are very similar to Queen Chrysalis and the Changelings in certain ways. Maybe that’s why I love them a lot and view them in a good light.
 
Well, they can eat like normal humans (and ponies.) do but to get people to like them, they have to learn that respect can be given by force.
 
@GuyverIV87  
I think of the negative energy as a power source rather than hunger replenishment.
 
@SuperSonic15  
If you’ve read the Sunset Shimmer backstory comic then yes. She thought she could become much stronger by becoming an alicorn right away and thought that friendship was just a petty unimportant thing.

@SuperSonic15
 
That’s pretty bad when someone 1 up’s your evil plan and is more effective.

@QuasarNova  
Good point.

@SuperSonic15
 
I know the guards have a bad repuation, but I still don’t see how bad they would have dealing with zombies that don’t have control of their powers

@QuasarNova  
Unless they were turned into their pony versions upon passing through the portal, like Sunset and Twilight did.

@SuperSonic15
 
Using teenagers? Flawless plan

@QuasarNova  
She did mention wanting to conquer Equestria. Maybe wanting revenge on Celestia for denying her becoming an Alicorn Princess due to her greed and lust for power?

@SuperSonic15
 
This makes me think on retrospect what Sunset was trying to do. A bunch of zombie teenagers, then what?