Princess Luna

Princess Luna, formerly Night Mare Moon, is a winged unicorn, the younger sister of Princess Celestia, and the antagonist in the first two episodes of the series. She is transformed back to her former self by the Elements of Harmony and returns to her duty of raising the moon and stars over Equestria every night.

Personality
As Night Mare Moon, she was vengeful, condescending, jealous, and angry because all the ponies slept at night. The legend that is narrated in the first episode tells that these negative feelings harbored towards her and Luna was transformed into Night Mare Moon in the first place. She appears much older and larger than her true self, and is comparable in size to Princess Celestia.

As Luna, she seems much more soft-spoken and gentle, and full of regret over her actions. She appears much younger and smaller, resembling the main cast of ponies. Little is known about her personality in this form, but she seems sad and remorseful when she appears in Ponyville. When the ponies present her with a wreath of flowers, she seems very touched and happy.

Lauren Faust has stated that Luna is not yet fully matured, and that there was some evil magic which transformed her into Night Mare Moon. When Luna is fully matured, she will not look like Night Mare Moon but instead ready to lose herself in pleasure.

Skills

 * See also magic

Like her sister, Princess Luna possess magic far beyond normal unicorn ponies. She is able to control the moon and the night sky, bringing them out each night and then moving them away to make room for the dawn.

As Night Mare Moon, she is able to take on the form of objects and other characters, among them mist, thorns, and a trio of pegasus ponies who present themselves as The Shadowbolts, the doppelgänger of The Wonderbolts.

History
In The Return of Harmony Part 1, Celestia tells Twilight Sparkle and her friends that when Discord ruled over Equestria, he kept it in a state of constant chaos. Seeing how miserable life was for earth ponies, unicorns, and pegasi alike, Celestia and Luna rose up against him. After they discovered the Elements of Harmony, they combined their powers and defeated Discord, using a spell that turned him to stone for eternity.

One Thousand Years Ago
One thousand years ago, the day and night cycle of Equestria was then ruled by the two sisters: Luna, the younger, brought the night, and Celestia, who brought the day.

Unfortunately, as the opening narrated in the first episode, over time Luna grew jealous of her sister: the ponies of Equestria all enjoyed and loved Celestia's daylight, but were all asleep at night. No one was awake to appreciate the beautiful night she had worked so hard to create. Eventually, this jealousy and bitterness drove Luna to become Night Mare Moon, and prevented Celestia from bringing forth the sun. She intended to keep Equestria in eternal night. Her older sister, with great sadness and regret, stopped Night Mare Moon by using the Elements of Harmony, and imprisoned her within the moon. Henceforth she became known as the Mare in the Moon and knowledge of her slowly drifted to the area of myths.

Escape
Eventually, a thousand years pass. The studious Twilight Sparkle reads about the legend which prophesied that Night Mare Moon will return on the night of the Summer Sun Celebration, held in honor of Princess Celestia and the longest day in Equestria. As foretold, Night Mare Moon escapes and soon appears in place of Celestia at the festival.

Twilight is the only pony, with the exception of Celestia, who anticipated Night Mare Moon's return; however, she did not warn anyone as Celestia encouraged her to use her time to make friends. Once again, Night Mare Moon desires to bring forth eternal night upon Equestria. Twilight knows that only the Elements of Harmony could stop her, and sets out on a quest to find them along with her five future friends: Applejack, Fluttershy, Rarity, Rainbow Dash, and Pinkie Pie. Having overheard this, the evil mare tries to stop them with different obstacles. After many hardships, the six ponies realize that their own virtues as a pony and a friend are the true Elements of Harmony. Using the six elements - honesty, kindness, laughter, generosity, loyalty, and magic, the ponies are able to transform Night Mare Moon back into Luna.



Redemption
Purged of her dark emotions, Night Mare Moon transforms back into Princess Luna. Celestia offers to put the past aside and start anew, with the two of them ruling Equestria together as sisters. Filled with remorse and shamefulness for her actions, a tearful Luna apologizes to her sister.

The two sisters are reunited and the balance between day and night is restored to normal.

Luna is last seen at the end of episode two, attending Pinkie Pie's party by her sister's side. She seems sad about what she had done in attempting to shroud Equestria in eternal night, but is cheered up when the ponies of Ponyville welcome her and wreath her in flowers.

Season two
Princess Luna has not made any subsequent appearances in season one. She is scheduled to return in the the episode Luna Eclipsed.

Appearances

 * See also character appearances


 * S1E01: Friendship is Magic, part 1 as Night Mare Moon
 * S1E02: Friendship is Magic, part 2 as Night Mare Moon and Princess Luna
 * S2E04: Luna Eclipsed as Princess Luna

Gallery

 * Princess Luna and Night Mare Moon image gallery

Trivia

 * Princess Luna, alongside Princess Celestia, were both based on the G1 Princess Ponies from the 1980s animated series.
 * Luna's name in Latin refers to the moon. Interestingly, the Friendship is Magic book, which comes with one of the gift sets of the toys, references her as Selena, "selene" (Σελήνη) meaning "moon" in Ancient Greek. More specifically, Luna is the Latin name for the Greek moon goddess Selene, who is the daughter of Hyperion and Theia in Greek mythology. Additionally, in the European French dub, Night Mare Moon was renamed as La Jument Séléniaque, which literally means "The Selene Mare."
 * When imprisoned in the moon, 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").
 * Night Mare Moon's title - "Mare in the Moon" - is a play on the mythological Man in the Moon.
 * Princess Luna and Princess Celestia raising the moon and sun respectively is based on Norse mythology, where the horses Hrímfaxi and Skinfaxi are believed to be responsible for pulling the moon and sun across the sky respectively.