This story is a sequel to Princess Celestia: The Changeling Queen

This story is a direct sequel to Princess Celestia: The Changeling Queen. Reading that first is necessary to understand any part of this story.

Co-authored by vren55 and Zervziel

Alternia, sister to Chrysalis, ruled Equestria for a thousand years, disguised as Princess Celestia, while the alicorn slumbered in a healing sleep. Now revealed, Alternia prepares to become Equestria’s first changeling princess, and prove herself to the ponies she loves at the side of her co-rulers Luna and the newly-returned Celestia.

But even as the crown descends onto Alternia’s head, something is stirring in the depths of the Eastern Sea, something that will turn the surface world onto its head. Some power that could destroy Alternia, and all that she loves, before she can even regain the approval of her own ponies.

Will Alternia restore the trust her ponies once placed with her? Will she found a hive? Will she find love?

All that is certain is that Equestria, and the world, will never be the same again.

Now with a TV Tropes page.

Empress Tethys and the Kelpies Created by Zervziel

That Fantastic Cover art is by Plainoasis

Pre-read and edited by:
Blankscape,
FinalFan,
Courage Fire
Cosmic Cowboy

To commemorate the imprisoning of Discord one year ago, the first annual Celebration of Harmony is starting off with a grand party in Canterlot, something Twilight Sparkle has been looking forward to after many sleepless nights plagued by nightmares. After a chance glance at the party, Twilight and Princess Luna rekindle their friendship sparked on Nightmare Night. Meanwhile, Princess Celestia grows worried over the state of her kingdom, her sister disappearing at odd times, and the seal placed on Discord. Are the princess's worries well founded or is her sister's oddly secretive behavior taking a toll on her nerves? Twilight gets caught between the sun and moon as both royal ponies reveal that there is much that history has forgotten about the nature of the alicorns and even the draconequus.

AU for not taking into account Season 3 canon.

Amazing cover art by Sai, check the image source for more of his great work!

Princess Luna arrives in Ponyville and begins to do wonderful things in the life of Twilight Sparkle. They become close friends...maybe even more, but when Twilight discovers that Luna may be after the throne the unicorn must choose whether to follow her head...or her heart.

One night, before Hearth's Warming Eve, Princess Celestia goes to light a fire to keep warm.

A voice in the chimney asks her not to do so.

After so many years, Sunset Shimmer is finally ready to return to Equestria. At long last, she will be able to reconnect with the land she was born in and feel the magic flow through her body once more. Most of all, she’s ready to face the mentor she betrayed, to apologize for everything and beg for her forgiveness.

Princess Celestia is eager to see her old prodigal student as well. Finally, she will have the chance to forgive her and reaffirm her love for her. What’s more, she will finally be able to give Sunset Shimmer what she has earned for herself and fulfill all the dreams she had since she was a filly.

At least, that’s how it was supposed to go.

Cover art by Bluse

Twilight Sparkle has spent months researching chaos magic, developing a new spell to unlock magic nopony has ever experienced before. But when something goes wrong with casting, Twilight finds herself turned into a Draconequus and unable to control her new chaos magic. If she ever wants to be a pony again, there is only one who can help her learn to control her new magic.

Of course, learning from Discord was never going to be simple. And after a while, being a draconequus doesn't seem so bad anyway....

Based on the concept by Lopoddity

Editing by DB_Explorer
Proofreading by Mac349 (Ch. 1-11), Trippy998, Just A Fabulous Cat (Ch. 1-5), Doctor Candor and skysthelimit (Ch. 1-11).

This story is a sequel to Deja Discord

With all that Twilight and Discord have gone through in their efforts to secure a place for him in both Equestria and pony society, with all the strides Discord has taken to appreciate them and realize true friendship, [as seen in A Pony's Sympathy and Deja Discord] there are still a few more obstacles to overcome.

With their home and their still-budding relationship at stake, Twilight might be required to take on the Spirit of Chaos - in all that that entails - to fully ensure that his place remains with the friends he has made, and with her.

The final story in the Sympathy Series. [Written between Nov. 2013 and March 2018]

Luna, confused because she has not been in a meeting with the Griffon Empire, overhears the Griffon ambassador and his companion talking about her. She then takes a decision that may change her life forever.

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First story, so try to be kind in the comments please.
Art: http://krrrokozjabrra.deviantart.com/art/Princess-Luna-359304544

Celestia asks Luna to teach Twilight dark magic. Twilight must pass Luna's class in order to graduate. As Luna develops feelings for her student, Twilight questions which princess she really wants to serve and protect.
(Twilight X Luna)

Princess Celestia has always been an incredibly busy pony who never has enough time in the day to do what she wants. Time seems to slip by as she struggles to get all of her work done.

One day, however, something terrible and unexpected happens, and more time than ever is lost to the sands. When Celestia reawakens, she'll find that her entire world is gone and that almost everything she knew and loved has long since disappeared.

A tale of sadness and of tragedy, the likes of which not often seen. Celestia, Princess of the sun...grand ruler of Equestria, and loving sister. Painful are the tears she will shed, and broken her heart will remain.

There is no greater pain than that of utter helplessness.