Included story:
 
After Queen Chrysalis was defeated and overthrown by her once loyal subjects, she was left with nothing. With nowhere to go and no sources of sustenance, she was powered by her own rage and hatred as well as the desire to protect her sole heir, a grub she had conceived with Shining Armor named Philia Agape Armet.  
Unwilling to reach out for help, Chrysalis tried to restart her hive on her own. However, limited resources rendered her barely able to sustain herself and her heir, let alone the hundreds of asexual spawn she tried to produce. She kept trying to make it on her own for a few years until she realized her half-pony grub would die unless she tried a different method.  
While Chrysalis was still unwilling to let herself be redeemed by the power of friendship, she knew that she had to form some kind of alliance with the ponies if she wanted to survive and retain her status. So, she brought Phil to the Crystal Empire to introduce him to his father. This ended in Shining Armor having a panic attack, Phil fighting with Flurry Heart, and Cadence failing to make everyone get along. Chrysalis knew this arrangement wouldn’t work out. Although Cadence offered to take in her new stepson and give him a better life, Chrysalis refused to accept her help. She took her child and set out to make some political deals with the royal sisters.  
Celestia and Luna were surprised to find the fallen changeling queen on their castle doorsteps with a young colt in tow. While Thorax had helped improve relations between changelings and ponies, the royal sisters were reluctant to take in an individual who had caused so much harm in the past. When Chrysalis proposed some political agreements, they reluctantly took her in under strict conditions.  
After Chrysalis was forced to prove her harmlessness, she and the royal sisters got to discussing ways to form a political alliance. With the situation Chrysalis was in, they realized that the most effective method of alliance was for her to enter a political marriage with one of the sisters. Celestia already had a child and was in love with somepony else, so she was out of the question. The only option was Luna.  
And so Luna and Chrysalis got married in the name of stronger political relations. Both were reluctant and neither truly loved each other, but they vowed to try and make it work for the sake of politics. Luna also adopted Phil and made a promise to protect him and help raise him into a suitable heir to the throne.  
Their marriage started off really awkward and rough, since it was formed on diplomatic matters and not love. Chrysalis was still vengeful towards the ponies and she and Luna argued a lot. At times, they even regretted making such a deal.  
However, Chrysalis eventually began opening up to Luna about her struggles as a fallen queen. Little by little, she told of her struggles in finding food for her subjects, the horror of having them all turn against her, and her failed attempts to make it out on her own. Chrysalis wasn’t normally this open with others, but she needed someone to vent to and it might as well have been her political wife. Luna soon realized that while she went about it in all the wrong ways, Chrysalis was just trying to sustain her hive as any ruler would do. She realized that she could bond with Chrysalis over their past misdeeds, so she likewise started opening up to her about her history. While Luna and Chrysalis weren’t in love, they began to reach a mutual understanding of each other.  
Over time, Luna and Chrysalis’ mutual understanding slowly blossomed into a romance. They kept insisting that their marriage was political, but there was definitely something more there. Eventually, Chrysalis decided to try for an heir to symbolize the “purely political” bond they shared. The two had a “political meeting” in the royal chambers one night, and soon after Chrysalis successfully produced her first larva in years. She and Luna named their new bug-child Firefly.  
With the arrival of their new child, Luna and Chrysalis were more successfully able to make their marriage work. While Chrysalis still scorned the ponies’ reliance on love and friendship, her thirst for vengeance eventually faded and she learned to simply tolerate it. She still refused to join Thorax and his colony, but she didn’t seek revenge against them anymore. Besides, her “diplomatic relations” with Luna helped her not feel so hungry anymore.  
As they worked out their issues and got to know each other, Luna and Chrysalis’ marriage turned out to be successful, especially for a political marriage. Chrysalis still doesn’t fit the ponies standards of “good”, but she tries to tolerate their way of life as best as she can. Luna has indeed had a positive impact on her.  
Despite their best attempts to raise him into a fine heir, Phil grew up to be an emo jerk. Part of this was due to his harsh beginnings, but most of it is just who he is. His family doesn’t understand him, but they let him be as long as he’s…happy and not hurting others. His father’s family is still freaked out by him, but they try to maintain some kind of relationship with him. He’s entered a polyamorous marriage with two ponies from another universe, so he is with them when he’s not lurking around Canterlot castle.  
Firefly, despite her parents’ best efforts, did not grow up to be the perfect heir either. She is flirty, sarcastic, and very mischievous. Even so, her parents love her anyway. She even reminds Luna a bit of herself in her youth, over a thousand years ago. Firefly’s birth as well as Luna’s marriage with Chrysalis has helped improve changeling-pony relations and strengthen Equestria’s team of allies.  
Chrysalis and Luna never knew their lives would take them to where they are now with their political marriage, but they’re quite happy that this is how things turned out. While they still have disagreements, they try to either work them out or agree to disagree. They now live contently with their family in Canterlot Castle.