I DON'T OWN STEVEN UNIVERSE OR YANG FROM RWBY.
Garnet was waiting in the sky arena for Jenny, the newest member of the crystal gems. Well that wasn't exsactly true. Jenny was the permanent fusion of Alyssa, the daterare of an old crystal gem and Yang, the girl form another reality Alyssa fell in love with after the crystal gem's enemy White Diamond sent Alyssa to several differint universes at the same time. Garnet saw a lot of herself in Jenny but there were a lot of diffrenses too. Jenny was still relitevly unstable in every day life. She would tend to split up if she was to stressed out witch was understand able seice she was just a teenage girl. All be it a teenager made of two other teenagers. But it was weird that Jenny was so stable during combat. It was proublly the fact that both Alyssa and Yang were trained to be protecters of humanity.
Garnet was snapped out of her thoughts as she herd the sound of the warp pad. Jenny walked into the arena and said "Hey Garnet, Pearl and Lapis told me you wanted to see me here." Garnet looked over Jenny and took stock of her one more time. Jenny's apperinse was strange enough. She had two black cat ears on top of her head that were real, long blond hair with blue strecks in it, a leather jacket that had two tails with the crystal gems star on the back, Jenny had the crystal green eyes of Alyssa but Yang's face and chest. She wore a yellow shirt with Yangs sembole on th front with blue jeene shorts.
"Yes I did. I want to train you to stay stable even during times of stress. So to do that I had Peridot make me something to help you train. But you don't have to do it if you don't want to." Garnet told her. ("What do you think about that Yang?" Alyssa asked.)("I think we should do it. We do need to be more stable when training Steven and Connie on how to use aura." Yang told Alyssa.) "I'll do it." Jenny told Garnet. Garnet put a strange coller on Jenny's neck and said "I put this coller on you and this is how it works. You will fight me for three hours straite and if you split up this coller will be on Yangs neck. If you do de- fuse then the coller will shock Yang past the point her aura can handle for her sembalense. It won't kill her but it will knock her out for an hour and after she recovers you'll repeat the training till you compleat it. Also Jenny the only powers you can use is Alyssa's gem powers and aura and Yang's aura and sembalense, that means no winter ice and no hellfire or help from Lasciel eather."
"No fair, Garnet." Jenny told her. "You've come to reliey on thous powers to much. Before Alyssa got her hellfire and winter knight powers she had to relime on her gem powers like sommining her weapon and her gem strength. You need to learn to use thouse powers, Jenny." Garnet told her. Just then Steven, Lapis and Pearl came into the arena. "Hi Jenny, we came to watch you train and I want to see Yang and Alyssa again." Steven said. "They want to see you too Steven." Jenny told him.
"Ok Garnet, lets train." Jenny told her as she readyed the hellfire calica. Garnet sommined her gantlets and got into her fighting stanse. Faster than the eye could see Jenny started firing shots from the hellfire calica. Garnet douged the shots and closed the disedense to Jenny and punched her in the stoumic. The force of Garnet's punch nearly overloaded Jenny's body but she maneged to stay together. "Dang Garnet, you almost overloaded my body. Last time I even took almost that much damege was when I first formed, I was punched through a four foot thick concret coulme. But you forgot Yang's sembalense and my own sembalense. SONIC SCREAM!" Jenny shouted, powering up the sonic blast with the power stored up from taking Garnet's punch. The sonic scream was so powerful it shorted out the coller. The sonic scream hit Garnet and split her into Ruby and Sapphire. Jenny then split into Alyssa and Yang. Sapphire was passed out and retreated into her gem and Yang could barely stand. "Wow. Alyssa, Yang your so powerful as Jenny. You actually beat Garnet!" Steven yeld. "Hey Steven." Yang said. "Good job kids." Ruby told Alyssa and Yang. "But this was suposted to be an endurinse test for your fusion stubilyty. Come on let's go back to the temple." Ruby told Alyssa and Yang.
Hi Dark Holt here. Sorry about the weird flow of this story but I was using this story to experiment with a future character I'm going to use. The character is Jenny. She's the fusion of my Steven universe OC and Yang from RWBY. But I won't use Jenny again till I finish my six story crossover story series. Side note- I wrote this story after watching the first episode of the Steven boam four the answer. I'm so stoked for the rest of the week and as a Steven boam event for the rest of the week I'll write a new chapter for one of my Steven universe story's a day. That's all. Dark Holt out.