For a few parts of this, I will just be rewriting a story from quotev. I'm rewriting Docile by Hatch-bad. Their story was awesome and I just couldn't accept that there wouldn't be anymore chapters, so I wrote my own and inserted my Steven Universe OC, Onyx!
Onyx is tall, like seriously. He's strong and has no recolection of most of his Homeworld memories. He feels a pull to Steven and the Crystal Gems, but mostly Steven. Whenever Steven is sleeping, he lifts up his shirt and stares at his gem. He knows he's seen that gem somewhere, but he just can't put a finger on it. Steven thinks he's seen him too, and at times when Onyx makes a certain move, quote, or even slight gestures, his gem glows. Also, when Rose or at time Pink Diamond, come up in conversation, Onyx's nose glows pink. Whenever someone is looking for something of roses, his nose glows brighter or dimmer depending on how far the person is away from the item.
Onyx is like an older brother figure to him, teaching him things about life, things he's picked up, or just ways to have fun. He loves making up songs with him, and can really handle some drums (much to Pearl's chagrin)
I'll add more to this as the story continues, thanks for tuning in!