language The Legend of the Crystal Empire

A young filly is discovered in the Frozen North

The unicorn daughter of the royal family changes crystallings for the better, and for this she earns her wings.

Due to the customs observed by the royal family, Nebula must be trained to become the next ruler of the Empire.

The royal family always consists of alicorns (though in regards to the king and queen, at least one has to be an alicorn. The other doesn't have to be). When the current king and queen adopted Nebula, they had no idea who her family was and did not expect her to have any royal blood. Yet she defied these expectations.

Nebula cannot rule alone, so a colt is chosen to receive tutelage and rule alongside her.

Years pass, and the day of the coronation arrives

Celebrations are held and gifts are bestowed upon the new king and queen.

One such gift is a stunning red gem, presented to the king.

The king and queen retire to their bedchambers, and Nebula is soon asleep, but Coal is drawn to the red gem.

A shadow stirs within the gem. Red light fills the room, and a pulsing sound can be heard.

Coal is tempted to touch the gem, and immediately finds himself in a dark, smoke-tinged void.

Coal meets Sombra, who is trapped within this void.

Sombra strikes a deal with Coal; the dragon king will share his power with Coal, and Coal must find a way to release Sombra from imprisonment.

Sombra is able to see through Coal's eyes into the surrounding environment.
The Crystal Empire is quite peaceful, and as a result, Coal has not encountered any ill-meaning individuals, and has no experience in this regard. He wishes to protect his subjects, and Sombra offers him 'strength.'

After agreeing to help Sombra, Coal orders a casing and necklace be fashioned for the gem.

If concentrating hard enough, Coal may enter and exit the void within the gem as he pleases.
His body stands still when he converses with Sombra.
After wearing the Amulet for some time, he takes note of the fact that it seems to increase his own power.

Coal works on new armor designs for his soldiers, and sends out convoys to retrieve books.

He converses now and then with Sombra. He does not tell Nebula about the nature of the Amulet.

When Nebula tells her husband they are going to have a baby, Coal's desire for peace grows even more.

Nebula finally confronts Coal over his strange obsessions.

When Coal reveals he desires total peace, Nebula implies that without hardship, one cannot grow.

Upon entering Sombra's domain once more, Coal realizes what has been transpiring.

In the time Coal spent wearing the Amulet, Sombra's power -- and influence over Coal -- slowly grew. He now knew the way out of his prison, and no longer needed Coal to search for one.

Coal feels a strong pressure in his mind as Sombra gains control over him.

A pegasus filly is born to the king and queen, and a royal crystalling is planned.

The day of the crystalling arrives, but it does not go as planned.

When the crystal ponies feed their love and power to the heart, Sombra siphons it away and takes it for himself. This fuels his transformation into King Sombra.
He uses the Dragon Amulet -- the last remaining piece of his old body -- to transform Coal's body into Sombra's dragon one.

King Sombra uses his magic to kill the previous rulers.

The previous queen was acting as crystaller, and had the new princess with her. Thankfully the princess was not harmed, as somepony rescues her before she falls.

Though Nebula had not been trained in combat magic, she engages Sombra, who is not yet used to his new body.

When King Sombra gains the upper hoof and strikes Nebula down, she destroys the Dragon Amulet with a beam of magic.

The resulting explosion sends both ponies flying.

Though Nebula managed to destroy the Amulet, this did not reverse the effect it had on Coal, and King Sombra became the new ruler of the Crystal Empire.

In her weakened state, Nebula cannot stop King Sombra from taking her prisoner, and locking her up at the top of the castle with the Crystal Heart.

To make sure her subjects stay in the Empire, King Sombra forces her to cast a spell that surrounds the Empire with walls of shadowflame.
An extremely fierce blizzard springs up in the Frozen North.

Assuming the Crystal Ponies will attempt to rescue their queen, King Sombra experiments and strengthens his defenses.

He craves crystals, but cannot eat them with his pony teeth.
However, he can drain their essence using magic, and drained crystals can be used to nullify magic (though shadow magic is an exception). In addition, absorbing the essence of crystals gives him the ability to grow them at will like rock-solid foliage.
He creates a web of illusions on the path to Nebula's prison, so that if anypony got past him, they still would not reach her.

Several servants attempt a revolt, and King Sombra quickly stamps it out.

He uses this opportunity to experiment with the drained crystals, and creates a spell that allows him to control the minds of ponies. With these he makes a small army of soldiers.

King Sombra sends his new soldiers on a mission; kill every single unicorn and pegasus in the Empire.

He knows unicorns have magic, and pegasi can fly. He does not think the earth ponies will be able to do anything to him.
The newly born pegasus princess eludes his best efforts to find her.

In central Equestria, Celestia and Luna take notice of the absence of skylights and envoys from the Crystal Empire, and send a team of soldiers to pay the Empire a visit.

When the soldiers return, they report the blizzard and walls of shadowflame, and the two sisters suspect trouble.

They make the decision to leave the soldiers in charge of their castle, and set out to investigate.
During their time away from the castle, Discord escapes from Tartarus and takes over.

Celestia and Luna use their magic to get through the shadowflame wall, and enter the Crystal Empire.

When the Crystal Ponies try to have the sisters protect their crystal princess, King Sombra's soldiers find them and capture Cadence.

Celestia and Luna are escorted to the throne room, where they meet King Sombra.

The sisters do not recognize him as the king who started the Dragon War, but Sombra recognizes them fairly quickly.

Sensing the vast amounts of magic the sisters possess, King Sombra leads them to Nebula's prison so he can apply magic-nullifying crystals to them.

King Sombra miscalculates, and the sisters are able to overthrow him, turning the tyrannical king into shadows.

Nebula is freed and helps defeat the king, at the cost of her life.

Celestia and Luna rescue Cadence and intend to help the Crystal Ponies, but before they can, the Crystal Empire vanishes into thin air.