Her quill floated above the letter, ink slowly dripping on the paper, staining the empty sheet. She wanted to reply. She really did. But she promised. Promised herself she'd stop. To shut herself of when her sister came back. She thought it be easy. She thought it wouldn't hurt. How wrong she was.
Over the years, from the day she stopped Twilight's magic outburst, to the day Twilight saved her sister and destroyed Nightmare Moon, she had gotten to know her faithful student more and more. Eventually she didn't see Twilight as her student anymore, but almost as a daughter.
But now she had to let her go. For her sister.
It's because of the amount of friends she made back then is what caused Luna's jealousy and hate. Because she made friends and Luna didn't. Her friends caused her to become more and more distant from her sister, to the point where she couldn't even see that she was jealous. It taught her one of the most important lessons: Friendship is magic, but magic isn't always good.
And now, to not hurt her sister like that again, she had to distance herself from Twilight. She had to, It was a necessary evil.
So, why?
Why did it hurt so much?
And everytime she received one of Twilight's letters, it hurt more. And more. And she had a feeling it would never stop. Not even if Twilight died. Not until she died herself.
Faust only knew how long that would be.
She had to resist the urge to answer every letter. She failed the first few. Why did she sent those gala tickets? Why did she subject herself to even more pain? She knew why. And she hated the answer.
She loved Twilight. She still does at this very moment.
And now she had almost written back again. She picked up the stained letter with her and threw it away, automatically grabbing a new one.
She stared at it for minutes, though they felt like hours. She then placed it on her bureau and picked up her quil again, levitating it to the paper. She dipped the quil in her inkwell, brought it back to the paper, and wrote
Dear Twilight Sparkle,
I'm sorry.
Signed,
Celestia.
As she stared at the letter for a few more seconds, a tear rolled down her face, falling on top of the letter, leaving one single stain on the last letter she'll ever write to Twilight.
It hurt.
She picked up the letter.
It hurt so much.
She rolled it up.
She despised the pain.
And she sent it to Twilight.
But the pain was necessary. It was her punishment for hurting her sister all those years ago.
She just wished that she could've spared Twilight.