The last thing she remembers is a ray of light
Sending her away at the end of her fight.
...
Luna woke with a loud, shuddering gasp and sprung to her hooves almost immediately. She looked with wide eyes at the emptiness surrounding her, moving her head wildly as she tried to find a source of light. Her breathing became heavier and more rapid as she shakily laid herself back onto the stone beneath her.
"Hello?" she said into the blackness, only to be greeted with more silence.
She had no clue what had happened. She just knew she was in a lot of pain, she was alone, she was a hurricane of broken hearts and sore muscles, she had only her mind to keep her company. Not much different from her daily life. But now it seemed that the world had ceased to exist.
"What in Equestria is going on?" Luna whispered to herself. She wondered if there had been some huge disaster. She wondered if this nothingness was what death felt like. Her already frantic thoughts moved faster as possibilities swirled around in her head.
Luna suddenly found herself yelling into the atmosphere. "I should have prevented this! I- well, I'm not really sure what happened, but I know I should have done something to stop it! Or...maybe I did do something? And I just wasn't strong enough? I should have been strong enough! And- what about-" Luna still couldn't see an inch in front of her, but she felt the shock of realization take over her face.
"Celestia! Is she somewhere here too? Did she try to save the kingdom too? What's going on?! I demand answers!"
Luna's voice echoed across the dark landscape as she stood once again. She pushed off of the ground, spread her wings, and flew as far as she could, not even knowing where she expected to find answers, or who she needed them from.
Eventually she tired herself out and landed, feeling more faint than she ever had before. Whatever, maybe this is just a dream and I need more sleep, Luna thought as she felt a tear slip from her eye.
As she lost consciousness again and her thoughts quieted, a sudden memory found its way into the front of her mind. She saw flashes of dark blue light, heard flashes of evil laughter.
She was the disaster.