Nightmare Moon

Nightmare Moon (ナイトメア・ムーン, Naitomea Mūn) is the name of the form initially taken by the bitter Princess Luna when transformed by the Nightmare Forces, and the main antagonist of the season one premiere of Legend of Mystical Heroes.

"Remember this day, little ones, for it was your last. From this moment forth, the night will last forever!"
 * —Nightmare Moon.

Appearance & Biography

 * Voice actor: Gina Torres (English), Yumi Uchiyama (Japanese), Not Known (French), Elda Olivieri (Italian), Jill Böttcher (German), Not Known (Hungarian), Ella Pyhältö (Finnish), Not Known (Korean), Mirela Corbeanu (Romanian), Olga Zvereva (Russian), Jelena Petrović (Serbian), Josefina Hylén (Swedish), Not Known (European Spanish), Magda Giner (Latin American Spanish), Not Known (Brazilian Portuguese), Not Known (European Portuguese)

Biography
Nightmare Moon is the malevolent alter ego of Princess Luna. In the dark form of Nightmare Moon, Luna is consumed with spite and enjoys manipulating unwilling ponies to do her bidding. Imprisoned in the moon, Nightmare Moon became even more dangerous when she escaped.

Personality
Much like the archetypal, over-the-top villains, Nightmare Moon is overly confident of herself and dramatically declares that the protagonist is a fool (foal) for thinking she can actually defeat her, and that "the night will last forever." She is portrayed as vicious and maniacal, shown when she attacks Princess Celestia and cackles evilly in Princess Twilight Sparkle - Part 2.

Bitterness
The narration at the beginning of Friendship is Magic, part 1 speaks of Luna's bitterness which transformed her. When she first appears, she intimidates the ponies with her evil laugh and pointed questions. She snidely refers to the ponies as her "beloved subjects," but appears genuinely impressed when Twilight Sparkle recognizes her as Nightmare Moon.

Manipulation
Nightmare Moon uses her magic to set obstacles in Twilight and her friends' path to the Elements of Harmony indirectly, making creatures unwittingly assist her. These include the manticore, whose paw she embeds with a thorn so he'd attack the ponies, or Steven Magnet, whose mustache she cuts off so he'd make the river impassible. She further indirectly attacks the ponies by causing a cliff side to collapse underneath the ponies' hooves and by making trees appear as monsters. As the Shadowbolts, she tries to persuade Rainbow Dash to abandon her friends so they won't be able to cross a fallen bridge and reach the Elements of Harmony.

Despite her indirect approach, when she is attacked by the royal guards, she quickly repels them with lightning, then turns into mist and floats away. Nightmanre also confronts Twilight Sparkle directly when the two charge at each other, right before shattering the Elements of Harmony.

Shape shifting
On multiple occasions, Nightmare Moon turns her entire form into mist. She appears in this manner in Ponyville's pavilion where the Summer Sun Celebration is being held, and she follows the Mane Six on their journey for the Elements this way. While in this form, Nightmare Moon manipulates creatures and environments; she transforms into a thorn to hurt a manticore, prompting it to attack the Mane Six, and she transforms into the Shadowbolts at one point.

Weather manipulation
Nightmare Moon uses lightning to repel the royal guards in second part of the first episode and thickens the mist over the fallen bridge later in the episode to prevent Rainbow Dash from hearing Twilight Sparkle calling out to her.

History
The beginning narration continues by stating: their subjects, the ponies, played in the day but "shunned" the night and slept through it, which made the younger Alicorn grow bitter, eventually refusing to lower the moon to make way for the dawn. Her bitterness "transformed her into a wicked mare of darkness: Nightmare Moon." The elder sister: Celestia, reluctantly harnessed the power of the Elements of Harmony and have "banished her permanently in the moon," taking responsibility for both sun and moon, maintaining harmony in Equestria and the world.

The name incorporates several plays on words: "mare" as in a female horse, "night mare" as in a mare of the night, and "nightmare" as in frightening dream, derived entirely from the medieval demon which haunts a person's mind with the use of horrifying visions. In addition, when imprisoned in the moon, Princess Luna appears as a dark area on the moon's surface; a similar shape in astronomy is called a lunar mare (Latin for "sea," pronounced "mah-rey").

The season four premiere explores Princess Luna's transformation into Nightmare Moon in deeper detail. In a flashback, Twilight is shown the inciting argument between Princess Luna and Celestia, Luna stating she refuses to stand idly by while the ponies basked in Celestia's "precious light." She angrily declares that she would be the only princess in Equestria, and during an eclipse, she transforms into Nightmare Moon.

Nightmare Moon attacks Princess Celestia with her magic, destroying portions of the old castle in the process. When Celestia retaliates with the Elements of Harmony, they prove too powerful for Nightmare Moon, and she is banished to the moon.