remember necron-lord you ask. you asked for my background story, and you get more than mine. moo ha ha.
this is the short version;
let's go back 1000 years to those giddy times, when Celestia and Luna first accended the throne of Equestria. Their power was unchallenged, but they were not direct decendents of the 'good' king who had establish Canterlot as the royal seat following the defeat of the dragon with the help of Star Swirl the bearded (some said he had died, but they would be wrong, for he had gotten feeble and old and returned to his old home near the Everfree Forest)
Like i said before the in-experienced Celestia's power was unchallenged, but her wisdom was. in a attempt to correct this, she got herself a dragon egg. Now before we go on, consider would a rose by any other name still smell as sweet. of course it would (or so claims the bard), therefore a dragconequus would also be a dragon. She named her new hatchling 'Cord" binding the heart strings of her heart in a cord to bind him to her. he was so cute them, and his mischief brought the princess much merriment.
Alas, there were many who found his antics most improper. Celestia in a bid to hide her embarresment moved to the new castle in the Everfree Forest. There her little charge could play more and so could Luna. but Cord harbored a bitterness against the new home.
And his malcontent turned to discontent, his mischief to maliciousness. maybe it was the forest or maybe he was just a bad egg. for whatever reason, Cord changed his name to Discord, cutting his ties with Celestia and seeking revenge on Canterlot.
we all know what happens next, Celestia and Luna recieve the elements of harmony from the tree of harmony and use their power to turn Discord to stone. But don't think this made Celestia's reign more secure. Sure she had saved Canterlot, but she had even more DIS-tractors, who blamed the clamity upon her, after all she had hatched DIS-cord.
Celestia had to spend more and more time in Canterlot, meeting all the requirements of pomp and protocol, This made her even more aloof from her sister. who still prefered the Everfree castle.
there Luna concieved the idea that she could 'eclipse' her sister. it was not her intent to take Celestia's power, only to show she was as strong a member in the team as her sister. her first step was to get a dragon egg of her own, she named it eclipse, but could not hatch it.
undeterred, she got a 2nd egg, named it 'star', and again failed to hatch it. getting a 3rd, she called it "knight', but still failed to hatch it. in desperation, she got a 4th egg, named it 'moon' and failed to hatch it.
this was when some terrible power took her in her sorrow and need, and transformed her into Nightmare Moon.
So Luna never had the power to hatch a dragon egg, but Nightmare Moon certainly did. She called her new hatchling(s) Sky. and them promptly confronted Celestia, only to be banished to the moon.
these four baby dragons, with one name, slunk off into the forest. they had enough wisdom to avoid Celestia, she had just banished her sister to the moon, she had turned her own pet dragon into a stone statue. it would be unsafe to be around her, until she matured. How many others did she turn to stone? http://youtu.be/mERpdDNeQaM
in the forest the four dragons named Sky found the hermit's home belonging to Star Swirl the bearded. there the old bell wearing wizard helped their heartbreak. Sky indeed had a broken hearts, abandoned by their mother "Princess Nightmare Moon", they poured their love for her into a statue of her as seen in season 2, episode 4. Doing so transformed them into ponies.
As ponies they claimed for themselves new names; Prof (S) Sum P, Lt O'Neigh, Uncle (K)Knot, and Mr. (Y)Yew. In short Sky became Sumponeigh Knot Yew. They became the four stars responsible for Nightmare Moon's release a 1000 years later. it took a 1000 years to devise a plan of resolution to deal with the insanity of Nightmare Moon, but Twilight Sparkle and the other elements of harmony interfered.
thus they have need of a double revenge, one against Nightmare Moon, for they would raise her and they should have been raised. they would regress her.
and 2, what would Spike do if anything ever happened to Twilight. do not doubt Sky in their desire for revenge, but they need to nothing yet.
let me explain, as the power that transformed Luna into Nightmare Moon, will probably seek out those most responsible for her 2nd defeat. So Twilight will be her next victim.
But Twilight is strong, surely she can resist? No she can't, she had never faced loss. how her heart will ache and groan when she finally does lose some pony. a parent maybe, one of her close friends even. No, not them, some pony even more important to her. Some pony who has been her mentor, her wise counselor, her guardian, and friend - Celestia herself.
Celestia cannot die, you say. Oh how wrong you are. Consider she had 1st picked Sunset Shimmer as her protege, now she puts her trust in Twilight Sparkle. Consider Sunset and Twilight are words associated with the end of the day. Celestia knows her end in near and she cannot prepare Twilight for that dark day.
will Sky be ready? does Sumponeigh Knot Yew have a plan? for when Twilight's grief becomes too strong?
moo ha ha, of course we do, we will have our double revenge.