Twilight Sparkle is the personal student of Princess Celestia, principal and founder of the Eos Dueling School. After her warnings about the possible return of an ancient, evil being are dismissed, Twilight is instructed to go to Ponyville and evaluate a potential Duel Monsters school. There she will meet an unlikely bunch of duelists.

Applejack, a farmer with high level dueling skills. Rainbow Dash, who doesn't know the meaning of the word "defeat". Rarity, who wants to dazzle the world with her dueling skills. Fluttershy, a timid girl who can see more than she lets on and Pinkie Pie, an energetic girl who wants to make others smile with her dueling. They will all have to work together to face the return of the Maiden in the Moon.

A humanized crossover with Yu-Gi-Oh!

A student is accidentally transported to Equestria through a crystal mirror. Lost and confused in an unfamiliar world, he struggles to get home. Circumstances conspire to make things difficult. The ponies he meets do the opposite.

Story starts between Season 6 and Season 7. After Equestria Girls: Friendship Games but before Legend of Everfree and the EqG specials.

Rated teen for language. Preread/edited by no one (in case it wasn't obvious). Cover art by some nerd.

Twilight Sparkle was just teaching her new pupil when the mare goes missing after Twilight asks her to take a break! Worried and angry, Twilight goes to Princess Celestia in a panic only for Princess Celestia to tell her that Starlight was kidnapped! But, by who? Who would do such a thing? (Contains TwiGlimmer)

After a portal experiment goes terribly wrong, Twilight finds herself on a strange world full of bipedal, magical creatures. She has no idea how to get back home. Maybe her new friends, a young Tauren and an Undead, can help her. They know of a magical city in the sky which might hold the answer to her problem. But can she really trust anybody in a world where true friendship is a rarity?

Knowledge of the Warcraft universe is not necessary to understand this story - but it might make reading it more fun.

This story is a sequel to Twilight Goes to Dalaran

Priest, the undead Forsaken, helped Twilight to get back home to Equestria - but now he is stuck in Ponyland! He has no idea how to handle this peaceful world full of cheery colors and friendship. On top of that, unsettling things start happening to him and rumors come up that there's a ghost haunting Ponyville...

2nd installment of the Twilight Goes to Dalaran series.
Knowledge of World of Warcraft is not necessary to understand the story.
Warning: Spoilers in the comments!

In the quest to save the two weakening alicorns, Twilight and Sunset will travel across Equestria and even into the Princesses' past to get the answers they need.

Everyone will have to fight to save their home as they know it from creatures of darkness that are growing ever stronger and will try anything to stop Luna and Celestia from reawakening.

[Cancelled] After capturing Twilight during A Canterlot Wedding, Chrysalis decided that keeping her and Cadance locked up underneath the place would be too risky. Instead, she forced them through an ancient mirror-portal said to contain an impenetrable prison created by Starswirl himself, shattering the mirror in the process.

Now, Twilight and Cadance must adapt to a new world and new bodies. Without any magic at their disposal, they must attempt to build a new portal and prepare to face Chrysalis on the other side while also maintaining the guise of normal high schoolers. Luckily, they aren't the only ones interested in reaching Equestria, and they'll cobble together an unlikely alliance of beings from both sides of the mirror to help them in their quest.

A Canterlot Wedding and Equestria Girls AU that, rather than aiming to be a fixfic, simply takes an alternate (and perhaps longer) path.

In a reality that Humanity has always existed on the same planet as Ponies and all the other creatures who inhabit that planet, this story follows Centurion Lucius Vor. The Roman Empire has expanded her reaches and sends her Legions to break all those who disagrees. Equestria being one Nation that prefers peace over all was just another nation on Rome's list. That was until the fatefully day of the VII Legion: Invictus fall from power along with many other Legions.

Lucius, even war stricken, tries to find the clear path but is only forced to bring memories back to light by a persistent Mare. Dark forces move against an entire Planet and threatens everything that all the Native species hold dear.

After an accident one fateful night Twilight has gained the power of a Planeswalker. Her adventure to get back home will be a long and argus one, or will she want to go home?

Luna is sent, along with young Twilight, to old Neighpon to try and quell the feuding warlords with diplomacy. And, if that fails, reduce the bloodshed as much as possible. Turns out that Luna is the kind of mare that likes to jokingly flirt and see how far she can go to make the other uncomfortable.
Boy is she in for a surprise.
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So the inspiration for a lot of aesthetic and naming is primarily Japanese, however I'm taking from all of the orient and I'm being fairly loose with the accuracy. Translations and terminology won't be exact, don't expect a historical rendition of feudal japan in pony form here fellas.
Will update tags if more of them become relevant.