Nightmare Moon on the other hoof was having a whale of a time, the hole she was fucking was tight yet malleable, warm and wet, the clapping of balls against Twilight's thighs matched only by the sloppy moist sounds of her dick repeatedly pounding the purple pony beneath her. Considering it was Nightmare's first time owning and using a penis, she lasted surprisingly long, but alas all good things had to come to an end, Nightmare Moon practically screamed in the royal Canterlot voice, ringing out through the caves and almost deafening Twilight as her balls churned and her cock throbbed. A full two liters of spunk crashed against every wall of Twilight's uterus, bloating her belly to an almost ridiculous degree. Pregnancy was guaranteed. Nightmare Moon was panting and sweaty, she waited for her release to finish before deciding it was finally over and with a great amount of tugging she freed herself from the grip of Twilight's body, leaving only an immeasurably gaped pussy leaking sexual fluids, excess cum and blood. Nightmare's cock and balls simply vanished after that, restoring her original female genitalia, the spell wearing off once she had removed the colossal cock from the moist caverns of Twilight's destroyed cunt.

As Nightmare Moon left the dungeon, she said "Thank you Twilight, your contribution to my reign will be written in the history books for years to come. Guards, prepare the prisoner for her freedom".

In the first couple of months of being released, Twilight had tried on several occasions to flee and find help or was actively trying to make sure the baby growing inside her didn't exactly make it to term. Nightmare Moon had expected this of course and had several contingency plans in place to stop Twilight from escaping, killing the baby or killing herself, she had thought of everything. Halfway through the year, Twilight gave up and figured that since she was now free, she might as well enjoy it... and she did. She laughed and chatted, she became maternal, ate lots of food and drink, she was like a normal pony again. The only thing that disturbed Twilight was not the affection for the baby, that was natural, but her odd attraction to the one who had put the baby there in the first place... Nightmare Moon. Stockholm syndrome wasn't part of Nightmare Moon's plan, but she welcomed it, it would be great to see the look on Celestia's face to see that not only had Equestria gained a newer, younger and more powerful leader, but that her faithful student had fallen prey to her sister to a point of being in love with her. That is of course, assuming Celestia ever escaped.

Twilight wasn't exactly bi or lesbian however and she had repeatedly pleaded with her lover, Nightmare Moon, to make the cock and balls she used a permanent fixture. Nightmare refused, but agreed to put them there whenever she was stressed out and needed relief or was simply in the mood for sex. The pair had done everything from blow jobs to anal and things were going according to plan even better than Nightmare had hoped, then one day, the baby decided it was finally time to break free. The birth was surprisingly easy and painless, most likely due to the fact that Nightmare Moon had previously fucked Twilight's insides open made muscles so weak they couldn't stop anything coming in our out. The result was a perfect little alicorn colt with dark purple skin, deep blue eyes that had a round-ish slit as a pupil and the same color of blue hair that was wavy but not ethereal, a prince of the night if ever they saw one. Nightmare Moon decided to name their son Kawani-Bulan for two reasons, one being that in ponish it translated to "Malevolent Moon", the second being a cruel and ironic joke, the name came from the language of the ponies that lived in the province of Jacanter, they spoke SUNdanese.

As years passed, a lot of things changed, Nightmare Moon had been prepared to send Twilight back down to the dungeon, only to find that she didn't really need to. Twilight had no desire to escape and had practically forgotten she even had magic even since being force to wear the inhibitor ring, the guards never seemed to report back with her acting any different to any other day, so either Twilight was playing the long game or she was simply content with her new life. However, Nightmare Moon couldn't take the risk that Twilight might secretly teach their son about harmony and love and all that useless nonsense and so, though it did actually pain her to do so, she kept their son shielded from the possible influence of Twilight's good-hearted nature. Their son had to be a hardened, cold and unfeeling prince if he was to inherit the throne, it was once Nightmare Moon explained that to Twilight that she understood and promised to stay away from him, no matter how much it hurt.

Of course as time passed, the prince grew more and more each day and Nightmare Moon taught him and trained him, shaping him to becoming the perfect ruler that would one day be able to defeat his aunt with ease should she ever return. Of course, other ponies grew old as well and the unfortunate event occurred where Twilight, his mother, simply died of old age. Nightmare Moon was somewhat heartbroken, she had to admit that she had grown unusually fond of Twilight during their time together, this however presented the perfect opportunity to test whether or not her son Kawani could be the iron-hoofed ruler that she had trained him to be, the one who would ensure that the night would last forever throughout Equestria and the world. She delivered the news of his mother's death to him.

He was shocked and of course felt a sense of remorse, but said in his booming voice "It is... regrettable... that such a fine pony should pass away and of course, a funeral will have to be arranged at some point, however that is not to say that such a tragedy should affect our current course". Perfect. Soon after that, Nightmare Moon decided she needn't continue to rule and retired early, abdicating the throne so as to make way for the coronation of the newest prince of Equestria, land of eternal night, prince Kawani-Bulan. He was just as strict a leader as Nightmare Moon was, perhaps even more so, he would certainly be able to rule for a long time before he himself would have to think about siring his own heir, there was only one challenge that arose though. It took around one thousand years, the same as it had for Nightmare Moon, but Celestia did eventually return, though not as herself. The creature that claimed to have been freed from the moon by the stars was what looked to be some kind burning pony demon that called herself "Daybreaker", prince Kawani had been trained to fight Celestia upon her return, not some raging beast version of her.

Which is why it made perfect sense that when "Daybreaker" decided to make a dramatic villain entrance into the castle, she was killed instantly. Sure it wasn't the traditional Celestia, but it was still her underneath all the anger and fire, she didn't stand a chance, the army and the prince were just more prepared than Celestia or Daybreaker or whatever had anticipated. What happened a few years later was something that nobody could have predicted, the prince was pondering the future, specifically when he would pick out a mare to impregnate to continue the monarchy. He knew that like his mother Nightmare Moon before him, he had to pick someone who was intelligent and powerful so as to produce the best offspring. The situation was awkward however, because he came to the conclusion that if he trod in the hoof steps of his mother, then there was really only one logical pony to breed with, the most powerful pony other than him, Nightmare Moon herself.

When Kawani confronted his mother about this, she said that he would of course have to settle for some other powerful pony, though the awkwardness of the situation didn't stop them from tumbling into bed together for just one bout of passionate sex, which fortunately didn't lead to a pregnancy. Suffice to say though, the night would truly last forever.

The End

Author's Note

Thank you TwiDavid for this story idea! I hope you enjoyed it! :)