Based on other stories of this premise. Also based on this story I forgot the name of but Adora and Catra form their own resistance with the Cadets.
The Whispering Woods, Adora looked down at Catra coming out of her tank. "Catra, please come on... Shadow Weaver will be furious if I let you defect..." Adora begged only for Catra to sneer at her.
"Oh please, you're her prodigy golden girl. I bet she is hoping you fail to get me back so she will have an excuse to order for my execution. I am done with the Horde and I am finally free of Shadow Weaver's grasp!" Catra retorted sarcastically. They spotted Glimmer and Bow coming towards them.
"New friends? Allying yourself with the ones causing chaos on Etheria..." Adora asked unimpressed but then Catra just snapped.
"Firstly, these two are no friends of mine, just some Rebels I had to ally with out of necessity. Secondly, wake up Adora!" Catra shouted in her face with a growl causing Adora to take a step back. "I saw the proof that the Horde are the real destructive force, which only confirmed which I always knew! We have been fed lies all our lives, you were always the smart one Adora so I am surprised you fell for it! I always knew the Horde were cruel and so was Shadow Weaver, you never saw that side of her being her favourite and all! I only stuck by because I knew I could count on you but I guess now I can't anymore..." Catra kept going on with tears in her eyes.
Adora just stared open mouthed at Catra, it couldn't be true. They were the heroes bring peace to Etheria, weren't they? She then had to dodge the boy Bow firing arrows at her and she stepped back as Glimmer passed Catra a sword and apologising for not giving it to her earlier.
Adora got up and faced Bow who looked like he was ready to fight, but then Catra held the sword and shouted "By the Honour of Greyskull!"She then transformed into a taller more muscular version of herself with a white dress, crown and red cape.
Adora was confused and decided to retreat for the moment, Adora and Glimmer looked like they wanted to go after her but Catra stopped them and said she would deal with her.
Catra found Adora who hesitantly looked up to her and asked "so is that the Sword that was calling to you?" Adora finally asked and she gave a nod. "So I guess you are with the Resistance now?" she asked again and Catra sighed.
"Not too fond of these two idiots but now I have gone AWOL I need some allies, they hate the Horde and so do I so enemy of the enemy and all that..." Catra muttered looking down with a tear in her eye. "So this is goodbye..." Catra muttered only for Adora to take her free hand.
"What are you talking about; once I get back from the Fright Zone with the other cadets you will not be alone." Adora responded making Catra take a step back. "I can't let you do this alone, I am not certain but if you're right about the Horde then you need all the help you can get!" Adora told her with a smile and Catra just stared at her.
"Won't Shadow Weaver be angry with you for leaving, do you really want to be her target?" Catra asked and Adora stared at her.
"As long as I got you it will be worth it." Adora told her and Catra told her that she will let the Resistance know they can expect new recruits, "One more thing, I like the look of you as Princess Catra!" Adora told her and Catra blushed.
"Thanks and make sure you don't get caught, without you I may have to resort to trying to make friends with those two and I am kind of dreading that idea..." Catra muttered as they waved goodbye to eachother.
Adora returned to the Fright Zone and Shadow Weaver seemed to be unconcerned about Catra's defection. She just told Adora that she was always the better of the two anyway and now they can focus on her future.
Adora just gulped silently and gave a slight forced nod. Early that night once she was sure that Shadow Weaver was preoccupied (having a meeting with Lord Hordak) she went to meet her fellow cadets.
"I have something important to tell you, Catra has defected to the Resistance and..." Adora told them and then Lonnie grew excited.
"No more dealing with her again, frankly we are better off without her especially since the Rebels will now have to deal with her hindering them!" Lonnie cheered to Adora's shock.
"Listen Catra says the Horde have been lying to us and they are the bad guys here..." Adora continued only to be again interrupted by Lonnie.
"Why should we believe anything that girl says Adora? We can't even trust her to turn up to training on time?" Lonnie had asked but Adora looked defiant at her.
"I am going to join her and I want you all to come with me." Adora stated as most looked on in shock, especially Lonnie.
"Are you mad Adora? You want to get on the bad side of the Horde, throw away everything we have been training for and for what? Catra is not worth it so we should just forget about her and focus on how much better off we will be without her and with you as our Force Captain." Lonnie stated motioning to the the two of them and the silent looking Kyle and Rogelio.
"Look I am going to join her, if you want to stay then I won't stop you but you are welcome to come with me." Adora told them going to the door but Lonnie stood in front of it. "What are you doing Lonnie?" Adora asked.
"Stopping you from making a big mistake." Lonnie retorted, she then continued "sit down, have a rest Adora and think clearly. We won't let you throw away your friends, all you have worked just for that stupid Catra..."
Lonnie was blindsided as Kyle had taken a broom and used the end to whack Lonnie on the side of the head, Rogelio opened the door as Kyle took Adora's hand and got them out of the door. Rogelio then shut the door and Kyle used the broom barricade the handle of the door.
"It won't hold her forever so we don't have much time to get a ship to escape." Kyle shouted at the two of them feeling braver than he ever did in his entire life. Adora just gave a nod as the trio rushed to where the ships where and got to work highjacking it.
"You two trust Catra?" Adora asked but they both shook their heads.
"I don't really trust Catra but I trust you Adora, you and Rogelio are the closest friends I had and I know you always were smarter than us. So if you think going with Catra to the Resistance is the right call then I trust you." Kyle responded with Rogelio nodding. Their ship managed to escape through the Fright Zone leaving their old lives behind.
Also leaving Lonnie to feel the wrath of Shadow Weaver...