Princess Luna has grown disillusioned with the elite of Canterlot. With the politics of the Night Court, dealing with keeping an eye on the hidden underworld of the aristocrats, and the lack of magical accomplishments in the last few years that weren't associated with Princess Twiilight, Luna wonders if it would be possible to have a student of her own to train in the lunar and darker aspects of the arcane. She's well familiar with the stories of Sunset Shimmer and Twilight Sparkle's training.
Unlike her sister, however, Luna has no interest in training a prodigy. What's the point in teaching somepony who learns everything so easily? She's set her sights a bit higher and opens her applications to anypony in all of Equestria, no matter their race. With her trusty aid, Night Shade and her "nephew" Blueblood helping her, it'll be a prospect to find the one that will be her first student in the years to come.
Why this story have AU tag?
7442535 You'll see eventually.
7442574 I swear to god your profile picture matches that reply.
I totally didn't make a profile after years of reading from this just so I could comment on your story or anything......
FEEL SPECIAL >:D
Dude I'm so into this, I can't wait for more chapters, I can tell this is gonna be a masterpiece :D
Twilight got the letter by accident I'm assuming?
7443091 You're very kind. Thank you!
Another Luna searching for a student story. I like this one so far.
Hahaha, I was hoping to make this joke in a fic. I love it.
It's also very interesting to see you reversing the usual roles Fancy and Blueblood take in most fics.
7451151 Well bats have their chirps and such so I thought itd be fun to include it as a language. As for Blueblood and Fancy... Watch the man who ignores his lessers but be wary of the man with nothing but smiles and friendship.
The Sisters don't really seem to have settled their 1000 year differences all that well, have they.
... except Twilight Sparkle.
It's kind of low, Luna, to set out from the start seeking to fail a specific applicant, accidental though she be. You could try just telling her the truth... 
7451480 As a teacher, sure. Not as a student however.. That's Luna's main point of interest. Plus the Element of Magic is naturally going to be amazing at all magic she's taught.
7451964 True... but Twiliiiight wanna leeeeaaaarrrrrnnnn!
7453404 She's been spoiled. Time for a dose of harsh reality, Twi.
Poor Dusk...
7538971 It can only go up!
*pokes* Hmm, another story afflicted by the not registering on tracking bug.
7613492 The whaaaaat?
7613772 It's that thing where it's on the tracking lists but doesn't actually show up on the unread list when a chapter comes out. Have had some stories go 5+ chapter updates before I notice them again.
I like this story. There aren't many Luna student stories out there. Most of them are in stage one incomplete.
7865855 I'm climbing out of the slump currently. I hope to update this soon.
Rest in Peace
I really like this story. I hope you choose to finish it someday.