The Nightmare glided across the ground, slithering low. She'd felt the Infinity Gauntlet being used. Even now, split apart and spread across the galaxy, each Stone returned to its respective owners, it called to her. It was time for her to step out of the shadows and claim her own again. And she knew just the pony to help her do that.

She found them quickly, sulking around. Silently, she glided to their ear and began to whisper.

"I know what you are feeling."

The pony jerked upright, turning their gaze this way and that. "Who's there?"

As if they'd be able to see her, in such a dark area. Her! Darkness itself! The very idea was ridiculous. "A friend," she hissed. "I feel your anger. Your desperation. You've lost everything. Princess Twilight and her friends took it from you."

"And what's it to you?" the pony demanded, eyes squinting, still trying to spot her.

She smirked, or would have if she'd had facial features. "Oh, how rude of me. I haven't introduced myself. My name is Infinity. I wish for sameness, for equality. For everything to last forever." She circled the pony, coming to rest in their other ear. "With me on your side, you never would have lost what you had. But with me helping you now, you can get it back. Everything can be like it was before."

The pony paused. "I'm listening."

"I'll give you power, power like you've never felt before. And knowledge, too, everything you could ever want to know to plan your revenge. You can destroy Twilight, her precious little school, and her precious little friend, Starlight."

The pony arched an eyebrow. "And what's in it for you?"

"Me? Well... I have revenge of my own. You're not the only one they've fought in the past. And they have something that belongs to me..."

There was no hesitation, no pause. "I'm in."

Author's Note

I tried to keep at least two possibilities for who "the pony" is open. Any theories?