At the behest of a friend of mine, I realized that I'd never actually sat down and drew out what any of my OC's from the story (Sometimes they call me Super) look like.
Brightness Slate is Star Slate's younger sister by ten years. Pre-timeskip, (2014-2018) brightness is 8-12 years old and braids her mane. She's very rambunctious and uses her wings more like that of a hummingbird to hover rather than soar. her eye sight isn't that great, but due to the death of her parents in 2014, there was little to be done about it.
She's a Power Pony, and her powers give her psychic abilities all revolving around her senses. she can detect and contact other ponies from a distance, as well as conjure visuals of places she's been. Anypony she's touched, she can track, and as she gets older, her abilities grow exponentially.
The caveat to her powers is that they take away her senses over time. By the time Brightness meets Firefly Flare in 2023, she's legally blind, but not to the point where her eyes might as well be useless yet. She can still see, but she doesn't get a score for her sight because she can't see anything at 20 feet away. As of 2030, Brightness is completely blind and only through manipulation of her powers and several other ponies can she 'regain' her sight.
What was once a happy young filly becomes a cold mare willing to do anything to end the madness that started all of this. She's a key player in the plot of Sometimes They Call Me Super, and the only one who really knows what is going on the entire time.