MLP/Undertale crossover.
Not a PWNY-verse story.

Long ago, the Monsters and Humans fought a great war. The Monsters lost, and were sealed in the Underground. It would take the power of seven human souls to break the barrier that kept them imprisoned. They only had six. And so the Monsters waited and hoped, praying that another human would find their way to the Underground. Some thought the seventh soul would give their King the strength to break the barrier. Some dreamed of a human who would be their friend, and save them all...or had nightmares of one who would bring back the war.

...but nobody came.

...but somepony did.

Eons after the war, with no way to tell how much time had passed above, a tiny blue filly with wings and horn fell into the underground, calling for her Mama. None knew the poor creature's nature or origins...but her soul was powerful with magic, even more so than a human soul.

None can know what will come...of this little 'Woona'.

Cover art by Sanyo21

This story is a sequel to Celestia's Tiny Student

(Title changed from "Ponyville's Tiny Librarian" for reason pointed in this blog )

Twilight Sparkle is a one-kilogram pony the size of a large rat, shrunken by Princess Celestia following her entrance exam to the Celestia’s School for Gifted Unicorns to ensure that her power surges would not pose a danger to the ponies around her.

She’s spent thirteen years full of hard training at her new size, facing the life-threatening experiences that came with living in a world of giants. To survive those thirteen years of hardship and joy, of learning and adventure, and of pride and humility, Twilight has challenged herself to be stronger, to overcome any obstacle.

Now that tiny Twilight is on her way to Ponyville to oversee the preparations for the Summer Sun Celebration, how well will this miniature mare fare outside of the confines of the castle? How will the other Element Bearers react to her? How will Nightmare Moon react to the tiny unicorn? Is Twiny prepared to face Ponyville, and, more importantly, is Ponyville prepared to face her?

Credits:
Art cover - kc day

Top editors: (editing and rewritting for months, hope quality is to your liking).
Kydois
Georg

Nightmare Moon's sentences editor:
Bahatumay

Applejack accent editor:
Crimson Star (Chapter 1 - Applejack)
Rebel Brony
The Notebook is grounded

Pinkie sentence's editor:
Plump it UP

Other editors:
Hereward
tana1100
Lab (small editing from prologue to chapter 4)

Pre-reader:
Rated Ponystar

To celebrate the release of this sequel, I created a group called “Twinyverse” for all fans of this story where you can talk about it and track all side stories with ease.
The Twinyverse Group

Imagine my surprise when I see a winged unicorn in my kitchen that claims she's my mother.

Imagine her surprise when I threw my coffee mug at her.

Imagine my Dad's surprise when I was banished to the end of Time.

Okay, the last part didn't happen, Tempora is actually really nice, but you get what I mean.

Just roll with it, I guess?

Based on an idea by Rainbow Dragon!

Edited mainly by FlameSwordedLink and now Grand Inquisitor.

Tag updated.

Future Chronicles now HERE
Kayla-verse linked here and in the story.

A damaged robot pony, unlike anything ever seen in pre-industrial Equestria, is found in the orchard. Before it collapses, it says only two words: "Twilight Sparkle..."

Twilight fixes the mechanical mare and gives her a new directive: "Make friends." Now a robot must learn what it takes to be a good friend and, while she's at it, what it means to live...

Featured on Equestria Daily (11/22/15) and The Goodfic Bin! (3/20/16)!
Featuring illustrations by Colby Green (Illustration Gallery found HERE.)
Editors: GaPJaxie,The Knight Templar, GenerousGhibli, E3gner, and Reese.
Technical Consultants: Artichoke Lust and JFalk.

Now with its own TV Tropes page!

Harmony through some of his father's shenanigans and his own temporal spells, seems to find himself in the future. He finds his family, but they're all grown up!

This is a side-story series published to make it easier for my readers to see.
If you came here somehow without going through the main fic it is highly recommended that you read it here. You will not get what is happening if you don't, sorry.

P.S. This will not be as rigorously edited as the main fic, sorry.

During the entrance exam to Celestia's School for Gifted Unicorns, Twilight completely loses control of her magic. Celestia tries in vain to calm her down, but having no other choice she's forced to use a shrinking spell on the filly in order to tone down her dangerous surge of power.

After the exam, Celestia takes the tiny Twilight as her personal student to teach the young unicorn control over her powerful magic, making sure that she will pose no threat to other beings.

Will tiny Twilight be able to step out into a world designed for someone far larger than her? And will her size impede her in the trials of life as princess personal student ?
Side stories: "My Little Twiny April Foals Day" and "My Little Medic"

[img]https://imagizer.imageshack.us/v2/109x149q90/138/zvuu.png[/img] [img]https://imagizer.imageshack.us/v2/136x137q90/843/7m25.png[/img]

Sub-autors:
Kydois (Audience <3!)
Georg

Editors:
kingtiger666
Ultra1437
Frozen Ice King

Pre-reader:
Rated PonyStar

Harmony comes home to see Tempora pacing around his house. Concerned, he asks what is on her mind. It's your father, she replies, something is wrong...

If you've somehow stumbled upon this without reading the main fic, it's best if you get it from HERE. This side-story is not standalone, it is highly recommended to read the main fiction to get what is going on. I don't usually publish fics unless they are completely original but for some of my readers this makes it easier. Sorry if the other method got too inconvenient.

This story is a sequel to MLA: Perihelion

It's been a handful of years since Twilight came into her own as a Princess of Equestria, a few years spent in peace and harmony without so much as an angry spirit or clandestine invasion to take away from the tranquility of Equestrian life. Unprecedented developments in the technological and thaumaturgical sciences seem to be preparation for something, though nopony realizes what that something might be.

Nopony except the Princesses, who have not failed to see the signs of impending disaster that began with the mass kidnappings just following the Summer Sun Celebration. When all their preparations are turned upside down, can an alliance with the mysterious Precursors turn the tides of the most devastating war in Equestrian history, while there is still anything left to save? Enemies and allies appear in the most unlikely of places, and friendship with a dying elder race can be more dangerous than an invasion of Dragons and Changelings. What is a pony willing to give in defense of harmony? What are they willing to sacrifice?

This story now has a companion piece, The Sunset Campaign! This story is designed to bring Harmony Defended more into line with the three-story version of My Little Apprentice. If you read Apogee and Perihelion, you may want to read that as well!

This story was written prior to season five, and as such any events which transpire therein may or may not be treated as canonical. All events up to and including "Twilight's Kingdom" are treated as having occurred, however.

A huge thanks to my Alpha Readers! Thanks to these wonderful people, new chapters aren't nearly so riddled with mistakes and errors as they used to be. Thanks to Sparktail, TwoBit, Withered Pyre, and Zutcha. Zutcha of course deserves double the love, since he's also the artist of the cover and any other fantastic art that finds its way into the story.

This story is a sequel to Nightmare Moon's Tiny Adversary

Twilight Sparkle is a one-kilogram pony, shrunken by Princess Celestia following her entrance exam to the Celestia’s School for Gifted Unicorns to ensure that her power surges would not pose a danger to the ponies around her.

She’s spent thirteen years full of hard training at her new size, facing the life-threatening experiences that came with living in a world of giants. To survive those thirteen years of hardship and joy, of learning and adventure, and of pride and humility, Twilight has challenged herself to become stronger, to overcome any obstacle.

After defeating Nightmare Moon with the help of her friends and the princesses, Twilight is ready to start a new chapter of her life in Ponyville. What kind of secrets and surprises await the little but powerful unicorn? Will this eventful town survive such an unpredictable citizen?

List of editors:
Top editors:
Nagel+Navari
Kydois
Georg
Plainoasis

Zecora lines editor:
Discord_Lexia

Luna lines editor: (helped a lot with old Equestiran)
bahatumay
Rated+Ponystar

Pre-reader (pointing out issues and giving suggestions how to improve the story):
Skydrake
Rated+Ponystar

Seconary editors:
lucia+merinero
Solstice+Shimmer
HeartLinda
tana1100
Pump+It+Up - some of Pinkie Pie's setences

If I forgot to add someone due to a long time that has passed, please PM me.