After being pulled from his nearly nine-hundred year stretch of hell in the dark abyss that is the Twisting Nether to serve the new Lich King, the Archlich Kel'Thuzad was faced with the dilemma of freedom from his bindings to the Scourge. He had been an advisor and (somewhat twisted) friend to the most evil being in Azeroth's history for nearly 15 years. He had butchered and enslaved thousands, spit in and stepped on nature's face with the necromantic horrors that were created aboard Naxxramas, and was a generally annoying raid boss, all while under the cruel tyranny of Azeroth's previous Lich King, Arthas Menethil...
But, when an Equestrian Lich King is appointed by Death himself in exchange for immortality, Kel'Thuzad is in for the surprise of his unlife when he is thrown into a large room, with two comparatively small, sentient equines, who claim to be the reigning Prince and Princess of a kingdom.

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

Twilight Sparkle never was a Unicorn and she didn't even know it.
What happens when her true heritage comes to light? Will she willingly embrace it? Or will she be forced to?

Beware of spoilers in the comments!

Edited by uTTerAbsurdity, Zervziel, Stormwatch and Gwenio

Cover art by the talented Cartoonlion and colored by the equally talented Stormwatch, original can be found here

Click here for the Tvtropes page

Seath the Scaleless, White Dragon God of Verdite, Traitor to the Everlasting Dragons, Duke of Anor Londo, Grandfather of Sorcery, and now the new friend and mentor to Twilight Sparkle? What will happen when two like-minded souls from opposite ends of the morality spectrum match wits? And what will remain in their wake?

A somewhat more meta twist on a MLP/Dark Souls cross-over, inspired predominantly by a few pictures I found of Seath and Twilight together, and my bewildered discovery that for all of the stories on this site that cover these two franchises, there's only one that focuses on Seath the Scaleless and so far it hasn't seen any updates in over a year ( http://www.fimfiction.net/story/68621/scales for those curious).

For those who haven't played either the King's Field or Dark Souls games worry not. I'll do my best to either explain the lore of both in the story itself, or add an author's notes for anything that gets referenced.

UPDATE: New custom cover art at last! Courtesy of Cryophase ( http://cryophase.deviantart.com/ )

Editing is courtesy of lunarstallion

In a remote corner of the Solana Galaxy lies a backwater planet called Veldin. Nothing important ever happens there. Nothing exciting, either. Ratchet, a Lombax with no idea of his origins, is beginning to grow bored with his life, and dreams of excitement. He wishes on a falling star for some excitement to find its way into his life.

The falling star answers by crashing into his home in the form of a basket carrying a tiny creature with a horn, a pair of wings, and four hooves. The name on the basket reads "Twilight Sparkle".
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Part of the PWNY-verse.

Edit: Now with cover art by the amazing G_Haze
Video Consultant/Technician: m2pt5 (he provides the infobot videos and similar.)

Edit: Game Timeline
Ratchet and Clank: Done
Going Commando: Done
Up Your Arsenal: Done
Deadlocked: Done.
Size Matters: Done.
Tools of Destruction: Done.
Quest for Booty: Done.
Crack in Time: Done.
All 4 One: Done.
Into the Nexus: Done.