She had decided it didn't matter. She had a cutie mark she never wanted, so she decided to become what was expected of her.
But she never expected it to lead to this. Not to death. She never wanted this karma.
Was there still hope? Could she change?

When Twilight Sparkle was transformed into an alicorn, she had no idea of the responsibilities the new station it would bring. Luna began training her to fight on the dreamscape. She tried her best to attend to the lessons, but was not expecting to be tested. Now that moment has come. She and Luna are in a fight, not only for their lives, but for the lives of every unicorn and alicorn in Equestria.
"Just think of this as a pop quiz." said Luna.
"You're not helping, Luna." Twilight said.
Note: Guest appearance by a character from Neil Gaiman's Sandman comic. You do not need to have read it to understand the character, which is why I'm not labelling it as a crossover.