This story is a sequel to Twilight Sparkle of the Royal Guard

Between castle gossip, professional rivalries, a blooming romance, and a mysterious malefactor still at large, Decurion Twilight Sparkle has a lot on her plate. Hopefully, she'll make a few new friends as she moves towards the destiny she's chosen for herself.

As per usual, big thanks to Magello for the rad cover art!

Twilight Sparkle broke time when she got her cutie mark. Now Twilight and Sparkle are sisters from another time. Twilight is hailed as the potentially greatest light magician of all time, and already has a reputation as a hero by the time she goes to Ponyville. This isn't her story, not primarily.

Sparkle is an orphan - her dark magic killed her parents. She lives with her brother in Canterlot's industrial sector because they can't afford anything better. She can't leave either. She's a natural dark mage; while Sparkle won't go mad like Sombra, her reputation is hardly any better. Worse, the law doesn't see her as a good pony.

The fact that the dead don't stay dead around her, or that Thorn - Spike's double - is an undead, soul-eating abomination, are other matters altogether.

(Also has some Slice-of-Life, but fimfiction tags won't let me put it with Adventure.)

Has an ask blog to go with it: Ask Sparkle and Thorn.
Also has a TvTropes page: Split Second Tropes.

Featured on EQD.

Cover art by Swirling Line.

When Princess Celestia asks Twilight to make an official, royal visit to Romaneia, Twilight dreads the inevitable succession of dry, boring diplomatic events. The charming Lord Bela soon wins her over, but Twilight is about to discover that all is not as it seems in Bela's apparently peaceful castle. (A story inspired by Carmilla, Dracula, and other classic vampire tales.)

Written for the BadassTwilight = Total Domination Twilight's Nightmare Halloween contest.

(Spoilers in comments.)

A normal day was all it took.
A simple failed prototype, a missed experiment.
There was an explosion, and I woke up. I don't really know what happened between those two events, but I'm fairly certain I shouldn't have awoken in a small, dark box.

I'm scared.

Cover art by the amazing Avatar of Madness!

Twilight takes justice into her own hooves, and enacts it on the enemies whom never really payed a price for their actions.

Tirek is in Tartarus, and Twilight has a certain power of his.

She must gain power to carry out this task. When she does, her enemies will know her wrath. But, is this really justice? Will the young Princess stop at her enemies, or will her rage run much deeper?

Rated Teen for Violence and light gore.

Featured on June 20th!

Twilight wakes up in a hospital near the border of Changeling country, but something about her is...off. She remembers nothing of her adult life, in fact she doesn't seem to be acting like an adult at all, and she seems to be juggling a bit of an alter ego. An evil alter ego. Maybe, when she took in the magic of the princesses, she took in a bit more than magic.
Cover art by Follow Focus

Twilight Sparkle has too much magic, and it will take her decades to learn to control it. Her spectacular loss of control during her entrance exam only proves that fact. She is a danger to herself and others.

After Sunset Shimmer’s disappearance, Princess Celestia needs a new student to bear The Element of Magic to defeat Nightmare Moon. With all of Equestria at stake, Twilight Sparkle…is not the pony she needs.

Princess Celestia seals Twilight Sparkle’s magic with the distant promise of one day teaching her.

But there are two diarchs of Equestria. Amidst a lucid dream, an offer is made.

“Hello, Twilight. Would you like to be my student?”

Cover art provided by Lafiir.

This story is a sequel to Lost into Shadow

The impossible has happened, through all the pain and darkness, Twilight Sparkle succeeded in her impossible mission...mostly. King Sombra is still plenty rough around the edges, but despite being an old dog he's making an effort to learn new tricks. Where will this new way of life take him? He has absolutely no idea, but with his queen to guide him, what could possibly go wrong?

This story is a sequel to Lost into Shadow

Twilight has failed, or rather, she has succeeded. Her darkness is her power, and together with her husband, Queen Twilight has a new plan for all of Equis. The black castle rises to greater power than has ever been seen before. War is brewing while alliances are forged and others are broken. The days of harmony are dead and gone, and all the world will be forced to mobilize against the might of the Nightmare Hordes. Will they prevail in the faces of Wrath and Despair? Do they have any hope of someday returning to a time of peace and love?
....
........
Not a chance, because in Chapter 1, Hope dies.

Twilight Sparkle is lost and broken, living a new life in a new town, she has forgotten who she truly is. Something happened to Twilight in Equestria that caused her sudden departure, and has half of Equestria scouring the planet for her.
"What did I do?" Is... not a question Twilight had thought of. She'd been happy, and content living her new life in Frostglade. However, she'd always felt like there were pieces to herself missing. Like, she'd lost something important.

When Sunset Shimmer and Trixie Lulamoon finally track her down after months of searching (and barely tolerating the other's presence), the reunion is not a happy one. Their presence has upset Twilight's new life by revealing the first step in unraveling the web of secrets bottled up in Twilight's psyche.

The three mares journey to a place of ancient magic, where they must piece together Twilight's shattered memories, solve the mystery, and then finally go home to where they truly belong. Of course, their journey will not be easy; dark shadows follow Twilight's every move, trying to stop her party from seeing the truth. If that weren't bad enough, it's not just Twilight Sparkle who is being tested by the challenges of the Nexus.