There are many legends whispered among the ponies of Equestria, but none are stranger than that of the metal man that fell from the stars. Legend has it that the metal man's suit of armor still exists to this very day, slumbering the centuries away in the Canterlot Archives ...

Takes place during the season four finale.

Here's some quick background info on what you need to know, seeing as the 40K universe is huge and no one can be expected to know everything.

The Space Marine chapter involved in this story is a little known chapter known as the Celestial Lions, who are a descendant of the Imperial Fists. They were targeted for destruction by the Inquisition after defying them on an Exterminatus that was due to purge a world the Lions had fought for and saved. They fought during the Third War for Armageddon mainly, and during the fighting, they were reduced from 950+ battle brothers to just 96. Their numbers are even lower now, due to events that will be explored during this story.

Edited and Proofread by the amazing Loyalist. He's seen some heresy.

Featured on 4/26/15 and again on 7/25/15

When Gaberdine is awarded a noble title by Princess Celestia, he soon finds out that his new lands contain several surprises. For starters, there is no land in his new barony. Secondly, his new castle turns out to be a broken-down riverboat. And third is… seaponies.

Baron Gaberdine has a lot to learn about his new barony. And himself.

Fortunately, he has a very young teacher.

Now with a sea-quill (sorry) Drifting Down the Lazy River

Cover photo by PhoenixSwift
Editing/Pre-Reading assistance by Tek, Shaleclaw, Peter, Seether00, Monsieur Connoisseur, GhostOfHeraclitus, The Masked Ferret, Blue Paladin42 and Admiral Biscuit

Note: Unlike The Traveling Tutor and the Librarian, this is a single POV love story, like Changelings, Love and Lollipops. Only with fewer cannons and fountains.
Now Featured on Equestria Daily
With a YouTube Reading of the first chapter by BigAsh
And with a dramatic reading by Neighrator Pony and company Full playlist here.
Thanks for a wonderful review by Paul Asaran
Available in paperback through Lulu.com at cost.

Strange nightmares are plaguing the ponies of Equestria.

Somepony must help ponies to face their deepest fears, but unless Princess Luna is able to discover who—or what—is responsible, the nightmares may never end.

Scootaloo is ready to prove that she can be as fearless as her big sister, Rainbow Dash, even if it means never having a peaceful night's sleep again.

Twilight and her friends enjoy a relaxing day at the beach, when Rainbow Dash has a startling encounter that leads to an exciting undersea adventure.

Featured on Equestria Daily on 09/28/2012

Two Pegasus head to Canterlot hosptial to have a check-up for their expected baby only to hear what no parent wants to hear.
I did not plan for this to be my first story but got some help to write it after some disturbing comments another Fimfiction user said to me.

A few years have passed since Princess Luna was purged of the evil known as Nightmare Moon by the Elements of Harmony. She took back her rightful place on the throne of Equestria at her sisters side.
On a sunny day, a couple of seemingly mundane events trigger memories long forgotten. Memories of a secret Luna hast kept to herself for far too long. Facing Celestia won't be easy. But she has no choice. It is her duty to care for her subjects, and she has to retake the responsibility she could not fulfill while banished to the moon.

In terms of full disclosure, the story got a review by TheifofZ.

What has happened since her disappearance? What will she find? A joyful reunion or devastation? What happened to her Children of the Night?

Inspired by Children of the Night. Cover art is a screenshot from the video. I do not know if there is an "official" story for the Children of the Night and I do not claim mine to be "canon" in the context of the video. These are just my thoughts on what might have happened back in the days.

This story takes place right before the season 4 finale.

My name is Twilight Sparkle, and 350 years ago, Sweetie Belle and I vanished without a trace.
Now here we are, in the future.
Equestria has become a utopia, with everypony living in peace and harmony.
Everything is perfect. All a pony could ever want, and more.
My name is Twilight Sparkle, and I want to go home.

Editing provided by Stereo_Sub and JustAnotherTimeLord.

Cover art courtesy of Geomancing.

Reading by lieilengi

Spanish translation by Spaniard Kiwi

Twilight Sparkle and her friends lived long, happy, and distinguished lives. Now, reunited in death, they learn the true nature of Equestria and the lands beyond and must face a task greater than any other: becoming gods to a new world.

Over the course of several years, Rarity has achieved a fabulous career, contributing to both Equestrian fashion and the Ponyville community. She is admired by her clients, envied by her peers, and cherished by her dear friends, proving that she's a dependable shoulder to lean on.

Then one day, a mysterious pony visits from out of town. She wishes to meet Rarity, but not to thank her.