You're the Mare in the Moon. Nightmare Moon.

The elder sister took on the responsibility for both sun and moon...

"For you see, the mythical Mare in the Moon is in fact Nightmare Moon

"Elements of Harmony: See Mare in the Moon?"

"Elements of Harmony: See 'Mare in the Moon'?"

The younger brought out the moon to begin the night.

"The Mare in the Moon: Myth from olden pony times.

I read all about the prediction of Nightmare Moon.

Defeated by the Elements of Harmony and imprisoned in the moon.

"Mare in the Moon?" But that's just an old ponies' tale.

How can I stop Nightmare Moon without the Elements of Harmony?!

Nightmare Moon: You still don't have the sixth Element! The spark didn't work!

Twilight: (gasps) But, where's the sixth Element?! (Nightmare Moon laughs, slams ground)

Twilight: You see, Nightmare Moon, when those Elements are ignited by the...

the very pony who gives us the sun and the moon each and every day,

then get to the library and find some proof of Nightmare Moon's return.

One fateful day, the younger unicorn refused to lower the moon to make way for the dawn.

Moon Dancer is having a little get-together in the west castle courtyard. Ya wanna come?

Using the magic of the Elements of Harmony, she defeated her younger sister and banished her permanently in the moon.

that we are on the precipice of disaster." Spike: Hold on...