When the newest Princess; Twilight Sparkle, was first establishing herself as a powerful figure in Equestria, it was not long until she build her own school, inspired by her wonderful teacher and own love for learning.  
The founding of a large new campus and school of course was met with a lot of trials and hurdles.  
Twilight was planning a widely inclusive lecture plan that was open to more then unicorns, to not just teach making but wide reaching subjects and allowing all sorts of creatures to strive for higher education.
 
At first, the other element bearers of course supported and helped Twilight out with her work, welcoming students and helping to work on classes, but all of her friends had their own plans and goals and were nowhere near qualified or eager to be longterm teachers for the facility.  
Researching and gaining dozens of applications of eager creatures, wanting to be part of this new exciting University project, Twilight was swarmed with people who would join the faculty before long.  
One of those intelligent and near over-qualified Ponies was Twilights fillyhood friend Moondancer.  
Moondancer was a dedicated Unicorn with more magic research under her belt then pretty much anypony else, a mare truly on par with the friendship princess herself.  
When Twilight first announced the founding of her school, she once again came into contact with Moon and excitedly invited her to be part of the teacher team, after a lot of hesistance and consideration, Moondancer agreed and made her way to join her in ponyville.
 
Not only did the school grow in members tho, Twilights castle staff did aswell, while never a fan of being coddled and warshipped due to her wings, Twilight did resign to the fact that the castle was too big for her to take care of all on her own.  
Other then an army of maids and servants tho Twilight treats the Crystal tree more as a home for her schools teachers and refuge for anyone in need of help, all being invited to carry their own weight of course.
 
Part of the actual staff of the castle is the royal guard that both Shining Armor and Celestia had to convince twilight she needs.  
One of said guards is personal guard Lightning Dust who was recruited by the princess herself, after Lightnings self-destructive dare devil appereances.  
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At the time Twilight and Pinkie have grown close enough to call themselves marefriends, while the rest of their friends moved towards building their families these two were just comfortable with each other, Twilight working on her school dreams and Pinkie moving into the castle to support her partner and help out especially in the kitchen !  
Another shared passion was the small abandoned bundle they shared custody over but that is for another time.
 
During the work on the school Twilight often was accompanied by her loyal guard Lightning as she was growing sickish, having restless nights and sudden bouts of sickness and fainting spells.  
Feeling under the weather more often then not Twilight put a lot of trust into Pinkie and Moondancer to overlook work on the school whenever Twilight herself did not manage to attend.
 
So with Twilight often sick at home, growing closer to her personal guard, Pinkie spend the same time at the side of vice-principle Moon, helping to oversee the school in Twilights absence.  
It might thus not come as a surprise that these two duos got quite close over this time.  
But of course it could not end well.
 
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