Though a long time has passed, Luna decides that the time has come for her to pick up her true mantle. For ponies have always viewed her as the princess of the night, and the night as her child. But, she has another child. A child that was born in the darkness of night, and only truly flourishes there. It is a child with emotions that rule everything. It can be summoned by anger, fear, or even just a surprise. And finally, after all these years, Luna has come to her child again. Because everyone else is to weak for the job, and someone else would've gotten it wrong.
Chapters (1)
So how many children does Luna have?
3138996 I'm thinking about doing a series of one shot's about it, but each sister has two. Luna has the two mentioned, who are the incarnations of night and death, and Celestia has a son and daughter who are day and life incarnate.
3140761
Nice. I'll read 'em if you do so as I think its an interesting idea.
Mind=Blown
so... so... WONDERFUL 
I demand moar! 
P.S. you win all of the mustaches
3147923 Thanks man, I always love to know that someone enjoyed my work. Then again this one has been in the chute for a while now. I'm starting a new side-series with 4 one-shots about each princess and her two children, I may or may not include Twi in this. But I thank you good sir. I'll throw a chapter on this one for one of the sequels.
Well, this was interesting. I'll favourite, like and follow. You kept my attention and interest.