Chameleon

It wasn't lining up, you found your color, didn't you?
Yes, it wasn't truly you, but it still corresponded in some part, most parts even.
The most out of every color you came across so far.

It's strange, everything is black and white in this world, but when colors appear, they are shaded with themselves.
You are black and white, yet a mix out of all the colors.

The hallways started to fold on themselves, becoming smaller and smaller, almost forcing you to crawl.
The long tunnel you engaged in was way darker than the rest of this plane, almost pitch-black. You needed to use your newfound front hooves to navigate whatever was here.

"Ouch!" That was your muzzle; you just bumped into a wall, but this one was different. It seemed friable, almost like glass, and even though you couldn't see much, you could swear this wasn't black nor white.

With a powerful blow, you shattered the wall, finally entering a wider room. The room was still white, but the small shatters of glass on the floor weren't; they were purple and pink.
Maybe that was your color?

No, purple is the color of magic, of the unknown, of corruption...
It's something mystic, something important, something defining,
And you were lacking definition.

"Focus, Dumb whatever-pony," you shouted to yourself. To who else could it have been for?

Take Twilight, for example; her purple symbolizes magic!
Now take Sombra, while mostly black, his dark magic is purple.
If purple doesn't define you, it outlines your own darkness.
But how can you come around with darkness? You don't have anything!

You turned on yourself, walking in circles as you reflected on what you were. Maybe it was pink all along?
While pink is just a pastel red, it has nothing to do with the beastly, bloodthirsty rage that emanated from that color.
Yes, pink was still radiating with energy, but this time it was pure joyful energy. Pink is lighthearted, pink is loving, caring, supporting...
Pink is the color of the heart over the brain.
But you don't have a heart...

Maybe you aren't made for colors.