Twilight researches an old artifact left behind by ancient beings who she believes were killed by an alien race that will soon invade Equestria. When she tries to warn everyone, they don't believe her. In order for her to save all of pony-kind, then rules will have to be broken.

Its been 50,000 years, and the cycle will begin anew. MLP/ Mass Effect

"If you're hearing this... then there is still hope. Hope that you can avoid the same mistakes we made. We fought the Reapers, but we failed to stop them. We did everything we could. We built the Crucicble, but it didn't work. We fought as a united Galaxy, but it wasn't enough. I only hope the information in this capsule is enough to help you before it's too late.

My name is Liara T'Soni. Herein lies the recounting of our war with the Reapers."

(Being familiar with the Mass Effect games would really help you in this story.)

An insurrection is forming in the Crystal Empire. The citizens wish for there once proud empire to stand once more! Princess Cadance must fall, and Equestria must be theirs! There is no existing military with the force to stop the new regime.

It's a good thing that 3rd Echelon technically doesn't exist...

A Splinter Cell crossover. Inspired by the Tom Clancy's Splinter Cell series and Stalkerloo. Splinter Cell is owned by Ubisoft. My Little Pony: Friendship is Magic is owned by Hasbro.

Its been 8 years since the Human-Covenant war ended. Humanity continues to rebuild after the war while looking for available planets to colonize. A young veteran and mute ODST that goes by the name "Rookie" due to his age compared to the rest of his squad is sent on a exploration mission on the UNSC Redemption when the ships AI goes under rampancy and sends the ship into uncharted space and the ships engines destroyed in the process.

The Redemption finds itself in orbit of an unidentified planet that is similar to Earth. They decide to scout the planet to see if they can see if it habitable or maybe even find help. what they find is completely unexpected.

SGT Jennings dropped into New Mombasa to take over a Covenant cruiser. When a lucky Anti-Aircraft shot takes away his ability to control his pod, he careens end-over-end into a slipspace portal, and emerges in Equestria.

Be warned, there is more cursing in the beginning then there will be later, due to an all-military environment in the beginning.

There is a legend. A legend of six heroes destined to protect Equestria from danger. But these six are not the Elements of Harmony. They are more.

The Steadfast Commander.
The True Genius.
The Vigilant Eye.
The Merciless Wrath.
The Fighting Spirit.
The Lone Wolf.

They are the true Protectors of Equestria.
They are the Guardians.
They are Noble.

Alright, so here is the story I have teased on my blog, The Noble Guardians! If you already guessed the concept, good for you! But for the rest of you, this is a Halo: Reach Crossover. I have seen a couple fics in which Six or Jorge are brought to Equestria, but they were always alone, so I decided to bring them all together as one. This will follow the show's storyline, with Noble acting as additional characters to the episodes, but don't worry, I guarantee they will be major characters with their own arcs and there will be plenty of original situations. I will also most likely skip any episodes in which Noble would have little to no involvement. (This will be few and far between, one example being "Call of the Cutie" I mean, even the Mane Six are only minor characters in that episode. I'll probably either mention those in passing or have another story going on with those episodes occurring in the background.) Anyway, see how Noble reacts to becoming Equestria's destined protectors!
Cover image credit goes to Gekko3309.
Naturally, this story contains spoilers for Halo: Reach

Pirates, adventure, and romance.
Rainbow Dash may have just gotten ahold of the greatest piece of useless blackmail material ever.

Peace reigns in Equestria in a glorious tone that rings throughout the land. Surrounding it are rival nations, each embroiled in their own bitter struggles, each looking upon the home of ponies with envious eyes. When all around them are currupted by greed, selfishness, and bitterness, how does this nation remain free of war?

Equestria's Secret Service is an organization hidden from the public eye. These brave ponies are unknown to the populace, and their brave deeds are ever unsung. In a world brimming with cold anger, hate, and violence, they move to prevent conflicts before they ever happen.

For peace. For Celestia.

For the good of Equestria.

Princess Celestia and Princess Luna are loved by all citizens across Equestria. It is common knowledge that they are both over one thousand years old. However, no one really knows where they came from, or how they came to be. When the princess of the night notices a strange star in the night sky, all that starts to change.

With Equestria under threat from a powerful new enemy, Princess Celestia calls upon four warriors from an alternate universe; four warriors with a special talent. They are descendants of our world's First Civilization. When they arrive in Equestria, Twilight Sparkle soon finds out that they are not so different from the princesses after all.

Rated T for language and violence.

NOTE: This story will contain spoilers for the games: Assassin's Creed II, Uncharted 2 and 3, Red Dead Redemption, and inFAMOUS 2, as well as the short film Assassin's Creed Embers. Read at your own discretion.

MLP © Hasbro
Assassin's Creed © Ubisoft Entertainment
Red Dead Redemption © Rockstar Games
inFAMOUS © Sucker Punch Productions
Uncharted © Naughty Dog, Inc

Injured during a surprise Changeling attack while trying to protect Cadance, Shining Armor is temporarily relieved of his duties and sent to Ponyville until he recovers where he runs into an intriguing mare.

(Rated for language, with intense violence and bloodshed, with alcohol and sexual references)

Story image created by GammaEradon at deviantART.

Used with permission.