At first glance, Princess Luna's charioteers might appear to be little more than Royal Guards dressed in festive apparel for Nightmare Night. However, there is far more to the story than that - the Night Guards once played a pivotal role in the history of Equestria, and have sacrificed more for their beloved princess than most ponies are even aware of.

Going up to the roof for some fresh air after pulling and all-nighter, our "hero" makes the mistake of closing his eyes for a bit.
When he opens them again, he is no longer on the rooftop in Copenhagen he was expecting to be on... no he's somewhere very different, and extremely unfamiliar.
How will he react? How will the ponies react? Nothing is certain, except for one thing...

He never asked for this.

This story takes place about 8'ish years after the second season of MLP:FiM, the language of Equestria does not match any earth languages (that the main character knows of at least), and the human in question knows nothing of these ponies or the world of Equestria.
He emerges into Equestria on the roof of a building in Manehattan, not the Everfree, not Ponyville and certainly not one of the princesses' bedrooms in Canterlot Castle.

Oh! Spoilers in the comments and all that jazz, not gonna go into a whole spiel about it.

Humans.

Truth or myth? Ancient lost civilization or just an old pony's tale?

No pony has ever seen one, and most haven't even heard of them. But Lyra knows that these wonderful creatures are more than just old legends, and she's going to find out... and possibly drive her roommate insane in the process.

The Princesses find an alien creature barely clinging to life at the scene of a terrifying crash. Can the Combined Power of the Elements of Harmony save it, or more importantly, should they save it? Will the arrival of this strange creature tear Equestria apart?

TV Tropes
https://tvtropes.org/pmwiki/pmwiki.php/FanFic/Article2

Twilight lives a comfortable, expected life with the security of being surrounded by her mentors and friends. As she grows into a model unicorn, a dangerous being takes hold of the volatile Brood and drives them to war, breaking a long period of peace. After years of preparation for a higher order, Twilight is chosen to ascend beyond that of a typical sorcerer in a mysterious plan to counter the impending conflict.

During her dark, trying mission Twilight will discover a caged soul and unknowingly set them free, gradually acquiring an affinity for the darkness as a result. As she struggles within deepening conflict, she must push on and fight for what she believes in. With manipulation, deceit, and betrayal storming around, will she be able to contain herself and protect those she loves, or will she succumb to the creeping darkness and abandon everything she stands for?

*Warning: Comments may contain spoilers.*

An archeologist finds himself pulled into a parallel world by Discord's storm of Chaos, and encounters the mysterious creatures that live there. How will a rational human, confronted by creatures out of mythology, and unable to find his way home, adapt to his environment? Only one way to find out.

Should you form attachments to mortals if you yourself will never die?

Losing the last of her friends in a battle that should never have been fought, Twilight Sparkle's world falls apart, until meaning and purpose come back into her life in the most wonderful way imaginable. But she forgets, again, that every living creature must eventually die...

Sequel to Not My Destiny, which you can read here. PG-13 for some mild psychological horror and plot-relevant, non-gratuitous injuries. I'll try to keep to the same chapter-a-day release schedule as I did back over New Year's.

Glorious cover art: Secreta Altare Window 3: Twilight Transcendent used with the kind permission of the magnificent confused--guy!

For almost a thousand years, the immortal Nightmare Moon has reigned over Equestria as Empress. To the average pony, Nightmare Moon is an overarching enigma whose rule is absolute and whose wrath is terrible. But to Twilight Sparkle, who as an orphan has never known her parents, the Empress is something else entirely. When the young unicorn is brought under the royal wing as an apprentice, she learns a great deal more about the supposed tyrant than she ever knew. But as Twilight is introduced to life with her new mentor, she is thrust into a world of political intrigue, conspiracies and secrets. Secrets that were never meant to be revealed. As allies and enemies plot against the very peace of the nation, will Twilight fall prey to the perils of her new position? Or will she prosper and find in Nightmare Moon the mother she never had?

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My eternal gratitude to my editor, LordOfTheWrongs, without whom Night's Favoured Child would not be the story it is today.

Now with added TVtropes!