Image imported from ponerpics 
Original Description:
 
Friendship Is Magic: The Next Generation begins thirty years after the birth of Princess Flurry Heart, and the story is… a bit darker and more complicated than My Little Pony: Friendship Is Magic before it. It delves into the backstory around Alicorns, where they came from, why Discord is the only Draconequus, and who is the prisoner in the deepest darkest cell of the cosmic oubliette that is Tartarus…  
(And admittedly, FIM:TNG does take some liberties with the events of MLP:FIM, mostly in regards to Equestria Girls and all episodes after and including The Cutie Re-Mark. That will become more apparent when it comes to the character bios for Sunset Shimmer, Flash Sentry, Starlight Glimmer, and others.)
 
Rounding out the last of these characters (for now) is Butterfly Affection, also known as Flutterbye, the accidental mind-child of Fluttershy and Discord. She is the oldest of the mane cast of Friendship Is Magic: The Next Generation, even older than Flurry Heart. She existed inside of Fluttershy’s mind since the events of Return of Harmony. When Discord couldn’t brainwash her into following the opposite behavior patterns she typically exhibited, he created a photonegative duplicate inside her and placed said personality in control. She stayed in there for a long time afterwards, at least until shortly after Discordant Harmony.
 
Flutterbye’s special talent is in causing miniscule changes to orderly systems to affect dramatic change, for better or for worse. She earned it from following in her father’s footsteps, complete with a snap of her paw. Her name is even a tip of the hat to the butterfly effect, the act of a small change leading to dramatic and often chaotic changes later on. This is a role she takes to strongly in the life of her little brother Windy.  
Flutterbye’s cutie mark on its own
 
Despite having Butterfly in her name, Flutterbye has more mothlike features. Discord found this discrepancy to be amusing despite Fluttershy’s protestations that it was nonsensical. Her wings specifically came from a real moth in our world: the rose maple moth, which has colors extremely reminiscent of Fluttershy. Her back left leg ends in a rabbit’s foot, based off the “lucky rabbit’s foot” which usually comes from a rabbit’s back left foot. If she was a natural-born hybrid of pony and draconequus, she would probably have more draconequine features, but because she was effectively incubated inside Fluttershy’s head for a very long time after Return of Harmony, she had relatively more pony features after Discord birthed her out of Fluttershy’s head. (please don’t ask how that worked)  
Flutterbye refers to Discord as Pops or Old Man, Fluttershy as Mom-Me, New Fluttershy as Other Mother, Rainbow Dash as Mother, and Pinkie Pie as Pink Mother.
 
The crux of Flutterbye’s personality can be summed up in “cruel kindness”. When she was first inducted into society out of Fluttershy’s head after so much time with only Fluttershy’s alter for company, she was still a cruel brute. But with a bit of tough love from New Fluttershy, Butterfly Affection was steered back onto the correct path. She was basically a newborn child in terms of malleability, and with Fluttershy and her alter acting respectively as good cop and bad cop whenever Flutterbye misbehaved, they were able to steer her onto a good path. She particularly uses this in relation to her “baby brother” Whirlwind, using her butterfly-effect magic to gently misdirect him into public situations to try to break him out of his social phobias. As to whether it is working or not… only time will tell.
 
As she grew up, she faced a lot of temptation to be an agent of chaos in Equestria as Discord had created her to be, even though this was no longer what he actively yearned for from her. Even New Fluttershy couldn’t keep Flutterbye in line on particularly bad days, at which point Discord was needed to lay down the law. She was still a piece of him, and so she fell under his power… for a time. He knew that the more time she spent apart from either him or Fluttershy, the greater her power would become and the harder it would be to rein her in without giving her enough reality checks. Of course, this wasn’t to say that Discord was a fun-killer for her. He wanted her to have fun with her chaos, and “cruel kindness” was a gray area he could fall back on to have his cake and eat it too.
 
Butterfly Affection’s colors are taken from Fluttershy when Discorded, with some exceptions. The fronds of her antennae are taken from the insides of Flutterbat’s ears, highly desaturated. The pink from the inside of Discord’s ear works for the color of her cutie mark. The spines on Discord’s tail and the color of his eagle claw are the colors of her rosy maple moth wings. Her eyes are a blend of Discord’s feathered wing and his lizard foot, and the lightest highlights are a gradient of his eyebrow colors to lighten up the cyan below it.
 
Fluttershy was aware of her mind-child’s existence almost immediately after Discord’s defeat in Return of Harmony. Much like in the Pony POV series, she saw the pale pseudo-Pegasus in the mirror and had a battle of the wills with her. She left it to her alter to keep the brute down. When Discord was brought back in Keep Calm And Flutter On, she knew that she would need to let Discord know of their mind-child sometime. Almost immediately after the events of Discordant Harmony, she swallowed her long-standing hesitation and spilled the beans, telling New Fluttershy to let Flutterbrute come to the forefront. It was… an immensely awkward first meeting of father and daughter. Pretty sure she knocked out Discord’s snaggle-tooth a few times. After they drew her out, Discord and Fluttershy tried to be a family together, but Discord could not stand spending long periods of time in Fluttershy’s cottage, nor could she tolerate long stretches in his domain. As Fluttershy & Rainbow Dash’s love bloomed, Discord found himself becoming a fifth wheel in Fluttershy’s life. He broke things off between himself and Fluttershy, and she felt awful for making him feel awful. But, it may have been too late. Discord owed her for their friendship, so she and her friends and family were safe. But they would only live so long. When they all died, and it was only him and Flutterbye, chaos would reign for a third time in Equestria.
 
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Since my Duchess Skystar was uploaded here, I decided to get on with uploading the rest of the Friendship Is Magic: The Next Generation cast.