This story is a sequel to The Celestia Code

When the monsters created by the dark crystal engine escape their prison, it's up to Princess Twilight Sparkle to deal with them. She gets help and advice from Princess Luna, but things don't go as planned. In fact, when a pony who relies on logic and rationality tries to navigate the stormy seas of emotional entanglement while simultaneously saving Equestria from a horde of evil creatures intent on destroying everything they encounter, nothing goes as planned.
AUDIOBOOK by VisualPony
WARNING: Major spoilers in the comments.

Book 2 of the Alicorn Adventure series.

Goodreads Page
100% Approved by Twilight's Library!

The Badass Twilight tag applies more than ever, but please note the new tags.

This story is a fairly direct continuation of The Celestia Code. You might be able to follow it without having read The Celestia Code first, but it's better if you do.

The sequel is here: The Twilight Enigma

Most excellent pre-reading/editing done by the erudite AcademicPony and the dapper statoose!

Princess Twilight Sparkle discovers a centuries-old mystery hidden in the Royal Archives. Her investigation leads through layer after layer of deception and misdirection, setting her hooves on a path that seems to be leading to a mysterious secret. Along the way, she learns that some friendships can be very, very strange.

Book 1 of the Alicorn Adventure series.

AUDIOBOOK by VisualPony
Featured at the Royal Canterlot Library
TV Tropes Page (Courtesy of Sandtalon)
Goodreads Page (Courtesy of Facedeer)
Equestria Daily Page

WARNING: Major spoilers in the comments. Takes place several months after the end of season four. (Not a Da Vinci Code crossover, BTW!)

Do you see a dark tag? No, you don't. Not dark. Well, okay, there are a couple of dark-ish bits, but that's all. Not enough to warrant a tag. Speaking of tags, there really ought to be "Badass Twilight" and "Friendshipping" ones.

Sequels and side-stories (and more) can be found here Offprint and AO3, and a hardbound two-volume set of all that can be ordered from The Ministry of Image.

My editor for the first edition of this story was Gogito, and I can't thank him enough for all the hard work he did. My editor for the revised version was PresentPerfect, and he did a terrific job of getting the story into excellent shape.

I was still a young colt when I took my first steps into the world of steam engines and railroading. I was meant to sing the song of steel, the chorus of the railways. Despite the challenges, discomfort, and dangers, I wanted to be a railway pony. I wanted a fine steam engine like #3803. I wanted to be like Highball.

What I got? Well now, there's a story worth telling...

This story is a sequel to That Changeling's a Pony!

Like most ponies, Maxilla the exiled changeling doesn’t believe that Daring Do is real. However, fate seems determined to prove her wrong in the most dramatic way possible.

After all, it isn’t every day that a changeling gets dragged along on an adventure and subsequently immortalised in Daring Do literature and merchandise.

The Elements of Harmony didn't work. Nightmare Moon won. Her beautiful night has been unending for over two years now, and her reign over Equestria is total.

Twilight and Pinkie Pie never gave up, even after everyone else did.

An infinity of praise be to Harwick for the cover art.

When a rampaging roc, deadly dragon, or horrifying hellhound threatens the idyllic snowy vistas of Equestria, it's the mission of the Celestial Slayers to protect the ponies, and hunt the bloodthirsty beasts that would harm them.

Rarity is one such Slayer.
A woman who has devoted everything to saving the lives of ponies, and ending the lives of monsters. For Rarity, there is no life outside the Hunt.

Except for her time spent at the Golden Oaks Library, flirting with the cute librarian.

A slow-burn, Raritwi-flavored Omniship adventure.
Inspired by Earthsong9405's Slayer!AU where Rarity hunts monsters and Twilight's a peaceful librarian.