Artist's comment:

Now I know she barely looks like it, but this is Amore! My version, at least. She was the original pretty pink princess before Cadence was around, and was in charge of handling the woes of the common ponies while her sisters handled the divine duties.

•Amore was the third, middle sister, between Celestia and Luna, and has since faded from history. Once upon a time, she was an earth pony.
•Celestia raises the sun, and Luna raises the moon, but Amore was the one that kept the world spinning. After all, love makes the world go round.
•She was the closest there ever was to a "Princess of Stability."
•Celestia and Luna were two extremes, and Amore sat firmly in the middle, balancing the other two out.
•Amore was turned to crystal and shattered by King Sombra, the second Pony of Shadows.

Celestia and Luna were devestated by the loss of Amore, and were quick to exact vengeance upon Sombra, tearing his physical form asunder and scattering him amongst the north as he did their sister. Sombra was, perhaps, more merciful than they were, as Amore could be revived by finding her pieces and putting them back together.

•Celestia and Luna did manage to put Amore back together, but were missing one crucial piece. The alicorn they brought to life had Amore's memories, but none of her warmth or kindness.
•Princess Papillion was literally heartless; the Crystal Heart is Amore's heart.
•Papillion did not like calling herself Amore, and was happy to disassociate with the name.
•After straining relations between her sisters and herself, she transformed, becoming a nightmarish reflection of how she was on the inside, and was subsequently banished.

Please don't take any of this too seriously, I'm just idea dumping. A lot of worldbuilding stuff goes on in my head and I want it out, aaargh.