Some Random Gemsonas

Yeah, we are going there, these are some Gemsonas I made for the lulz, back when SU wasn't infested by tumblrinas and SJWs.

Starring from left to right:

Raom Galaxy (gem - Zicronia): Wut? Another human gem hybrid you say? Yes, Raom was designed to be the opposite of Steven Universe (the character, not the show), while Steven was taken care off by three rock lesb- I mean Amethyst, Perl and Garnet.  Raom was born alone, despised by the human around him, (because you know, his gem power will occasionally pop up and kill people), instead of trying to help him out, the people of Raom's birth place launched him off into space via a makeshift rocket (this would explain why he isn't in the show). This gives Raom an aloof and cold personality, to play further into the antithesis of Steven, Raom hates humanity (as well as gems) with a passion. And sees no forgiveness in the way that he was abandoned by both sides. Well, sort of...

Velvet (the blue one): AKA Sapphire with longer hair, Velvet was once the second in command of a gem corsair fleet (a group of gems that weren't loyal to the home world gem or anyone for that matter), her captain was Zicronia (Roam's mother), they were hired by Rose Quartz during their war on Earth against the home world gems, after the war was over, Zicronia expected payment of human slaves. Rose, obviously not amused, censured Zicronia (probably the same way she did to Bismuth). Leading Velvet with the captain-ship of the gem corsairs. Velvet, after many years returned to Earth only to find a space capsule with a crying baby inside, sensing her former captain's essence, she brought Raom into the fold. Treating him as more of an asset than a person, Raom soon realized his combat potential after many boarding action and heists. Both he and Velvet never saw eye to eye.

Spinal (the orange one): AKA Pilot episode Perl jacked up to 11, Spinal is one of the few crystal gems out there who realized the advantage of projectile weapon and ranged combat. Combine this with her jet pack, she is neck to neck with Raom when it comes to boarding action. Feisty and fiercely independent, Spinal loves the thrill of the life as a corsair. 

Black Onyx (that black monstrosity in the back ground): created by a doomed civilization that once fought the gems, seeing they were on the verge of complete defeat, the scientists of the doomed civilization invented Black Onyx as a final gesture of 'you may have destroyed us, but we will take you with us'. Black onyx is a mindless living weapon that hunts and consume any gem that she came across, programmed for the eradication of Crystal gems in the universe, black onyx's power grew as more gems she consumes. Her only weakness: human gem hybrid, making Steven and Raom the only hope universe have against this relentless foe.