The Night Shall Last Forever

Twilight just sat in the middle of the cave, the magic dampening chains clamped around her legs were all attached to the walls leaving her unable to move. She was extremely malnourished, she was given so little food that the once reasonable amount of fat on her body had simply started to ebb away bit by bit, until she was practically skeletal. She hated the cruelty of her existence, the only reason she was alive was so that Nightmare Moon could rule and take pleasure in the knowledge that the only threat to her was left to rot in a dungeon contemplating just how much she had failed and wallow in her own guilt, shame and self-loathing. Everyone she ever knew and loved was now loyal to the enemy and for her, hope in Equestria had truly died, there was no saving the land or herself. She just wanted to die.

Which is why she was shocked beyond all belief when not only had her rations increased, but there weren't any rations at all. She was given all manner of wonderful food that stayed fresh thanks to magic, not to mention a multitude of different drink choices. Twilight was initially suspicious, this was just so out of the blue it had to be a trick, was it her normal rations disguised to look like tasty food? Was it magically induced hallucinations of food? Was it laced with something that might kill her? Actually, the thought that the food might kill her wasn't an entirely unwelcome prospect considering her state of mind at that point, she figured that she had nothing to lose and tucked into all the food and drink she wanted. It wonderful, it was all so wonderful, after tasting the food and drink and suffering no ill effects whatsoever she no longer cared why Nightmare Moon had allowed this and just couldn't believe her luck.

Time flew by as Twilight continued to enjoy the bountiful food and drink she was being provided with, she started putting weight back on, she looked happier and healthier, everything was perfect. It was just as she had reached a point where she was looking like her old self again, that she got a visit that she was never expecting by none other than Nightmare Moon herself, "Hello Twilight Sparkle" she said. This wasn't good, was Nightmare Moon here to mock her for being so foolish and that now she had eaten her fill she'd be taking all of the food and drink away again? Of course, how could she have been so blind? It wasn't a gift, it was yet another way to further her pain. Nightmare Moon continued "I am glad to see you are looking much better than before, you're the spitting image of the happy young pony you were when you first came to Ponyville".

Twilight said "Thanks, I suppose you're here to taunt me, break me down, take away all the food and drink and almost starve me to death again?"

Nightmare Moon couldn't blame her for thinking that, part of her even thought that would be an interesting thing to do in future, but now was not that time. "Far from it Twilight Sparkle" said Nightmare Moon "In fact for the next year I am willing to grant you all the food and drink you could ever want, total freedom within my castle, limited freedom in Ponyville because my guards will have to accompany you and that is it, granted I will have to insist you wear an inhibitor ring on your horn, but I am willing to give you all of that and more if you so wish. I want you to be happy and to be healthy Twilight Sparkle".

Twilight Sparkle was baffled, there had to be more to it than that "What's the catch?"

Nightmare Moon again went "No catch, that's what I want for you. As soon as we are finished up here, I will give you all of that of my own free will, the only thing that is non-negotiable is the inhibitor ring and the necessity to have two guards accompany you whenever you wish to venture outside the castle."

Something was clearly very very wrong here, why was Nightmare Moon being so kind to her? She decided not to look a gift horse in the mouth however and said "So... once this discussion ends... I'm free?"

Nightmare Moon nodded "Yes Twilight Sparkle... however, this is more than just a discussion..."

Twilight knew it, of course there was something, why did she think that Nightmare Moon didn't want something in return for all of this? It must have been very big and important if Nightmare Moon was willing to give her some kind of freedom for a whole year in exchange. "You see Twilight Sparkle..." said Nightmare "I intend to rule for a very very long time, however one princess cannot rule indefinitely, like any other pony I too will eventually get to a point where I will be unable to continue and thus must pass down the torch of my kingdom to a younger pony to rule so that I may retire. However, I have absolutely no intention of allowing my sister Celestia or indeed any other pony to take up my mantle, I need an heir while I am still able enough to train them in how the world works under my rule and how they will maintain it once they become the next monarch, I need descendants".

That all made sense, though their was the obvious question that Twilight needed to ask "What does that have to do with me and earning my year long freedom?"

Nightmare Moon smirked and continued her explanation "Well, the obvious answer to this particular conundrum was to find someone suitable to mate with, I've scoured the land for every possible male that had the qualities I was looking for and would would allow them the pleasure of spilling his seed inside my caverns, but no stallion on the planet met my specifications. I too also repeated the process with mares, hoping to use the so called "mare-to-male" spell on them, but again no mare was ever up to my standards... all except one that is, your pet dragon made it clear to me that the only pony who was genetically gifted, powerfully magical and also fiercely intelligent... was you".

Twilight was heartbroken, she knew where this was going, she was more horrified that even Spike had succumbed to her will. "You can't make me! Even if you cast the spell on me you can't force me to mate with you! Besides, these chains prevent me from doing the necessary... thrusts... so it's not happening!" Twilight realized her outburst of defiance may have been a bit premature as Nightmare Moon practically cackled at her.

Nightmare Moon said "Don't be ridiculous! Do you think I'd allow you your freedom if you were the one that was going to sully my exquisite nethers with the contents of your balls? Preposterous! No Twilight Sparkle, it is very much the other way around, you are to carry my child, once I deliver the contents..." Nightmare Moon paused as she lit up her horn, surrounding her body with magic, her skin shifted as her vagina closed up and practically vanished and the glow of her magic intensified which brought forth in her vagina's place a long, thick jet black stallion cock accompanied by a pair of massive balls. Once the transformation was complete, Nightmare Moon completed her sentence "... of my balls".

Twilight was deeply against this, but she doubted her consent had anything to do with it, Nightmare Moon would end up raping her one way or another. Nightmare Moon said "Now... I think we've had enough talking, so why don't you be a good little pony..." Nightmare Moon thrust her flaccid dick in front of Twilight's face "... and get this thing hard enough for the impending penetration hmm?" Twilight simply opened up her mouth, then as soon as a single inch was pushed into her mouth, she bit down as hard as she could, needless to say, Nightmare Moon was not a big fan of the pain Twilight was inflicting on her new genitalia.