Hyperdimension Neptunia belongs to Compile Heart, Idea Factory, Sega and whomever else worked on it.
Nepgear looked at the blue-haired girl with sad eyes. "You want to destroy Gamindustri?"
The girl, Uzume, she called herself, nodded and smirked. "Well, I guess I don't need to do much, huh, Gearsy?" The two were looking out across Zero Dimension. "After what you did to stop the Deity of Sin..."
"Stop it." Nepgear said, her voice full of exhaustion and regret. "After what I did..." She shook her head. "I won't let you destroy what's left of my world!"
"Gearsy..." The blue-haired girl smirked at her. "What does it matter? You sacrificed all the other CPUs and the Deity of Sin did tell you, didn't she? That even though there's peace, the world will slowly come to an end anyway."
"I..." Trembling as she gripped Gehaburn, Nepgear felt her shoulders slumping. "I know, I can feel it falling apart." She looked up and Uzume could see the tears falling out of her eyes. "I don't want to destroy the world. I want to go back to what's left of the Hyper Dimension."
"An empty world, devoid of the CPUs that made it so healthy and happy..." Uzume said softly, giving Nepgear a look full of pity. "Perfect for an empty CPU, huh?"
Nepgear said nothing as the blue-haired Uzume walked up to her and pulled her into a gentle hug. "U...zu...me?"
"I know what it's like, Gearsy..." Uzume whispered to her softly, "to be empty, to have nothing in the world." She said and rocked back and forth softly while Nepgear's tears spilled out of her eyes and she dropped Gehaburn to hug the former CPU of Planeptune.
"In a way, I don't have to do anything to get my revenge on Gamindustri, even if you work your hardest, the world will eventually end. Gamindustri needs its nations and CPUs to thrive." Uzume rubbbed Nepgear's back while grinning to herself. "Just stay here, Gearsy, stay here with me. Even if the world dies, you'll be fine."
"But I..." Nepgear looked up and tried to protest. "I have to..."
"There's nothing left for you there." Uzume whispered and Nepgear closed her eyes nodding. "Just stay here with me and I'll be with you for the rest of your life."
"That sounds... Kind of nice." Nepgear said softly as Uzume slid down and sat down, putting Nepgear's head on her lap, allowing the tired girl to relax and rest.
"GEARSY!" A voice so similar to the blue-haired Uzume suddenly yelled and Nepgear's eyes snapped open and she sat up as she saw the redheaded Uzume running at her.
"And things were getting so good." The other Uzume sighed as she stood up. "What will you do, other me?"
Uzume tried to ignore her questions about seeing a blue-haired version of herself and focused on Nepgear. "Didn't you tell me, Gearsy? Didn't you tell me that you respected me because I was trying so hard by myself? Didn't you tell me that you were as well?"
"I'm so tired, Uzume..." Nepgear muttered as she held out a hand and Gehaburn shifted and floated to her outstretched hand. "I'm just so tired."
"Putting aside questions of how you did that for later," Uzume muttered, though she was somewhat pleased to note that her other self was just as surprised as she was, "Gearsy, do you really think that the other CPUs would want you to give up?"
"And what should I do?" Nepgear asked as Uzume ran up to her while the other Uzume walked away, giving them a smirk.
"Grit your teeth, Gearsy..." Uzume muttered and punched Nepgear in the face so hard that Nepgear went flying back and slid several feet.
"...Not what I would have done." The blue-haired Uzume said while staring stupidly at her other self.
"Owwies!" Nepgear whined as she pouted at Uzume. "Did you have to use a fist?" Any further complaints died out as Uzume stood over her. "Uzume?"
"Dammit, Gearsy!" Uzume grabbed Nepgear by her shirt and lifted her up. "Look at you! This isn't like you! You told me that you wanted nothing more than to get back to your dimension because you're the only CPU left there! What happened to that?"
"What good is it?" Nepgear asked. "The other Uzume's right, Gamindustri's going to be destroyed without other CPUs, I... I have..."
"Nothing?" Uzume asked for Nepgear. "Really?" She dropped Nepgear on her butt and held up her wrist-communicator. "Wanna bet?" She pushed a button on it and some static was heard.
"...Gear? Gear?! Are you there?! It's me, IF!"
"I...F?" Nepgear blinked in confusion. "What..?"
"Dammit, Gear! Compa, Histoire, myself and everyone's waiting for you to come back! So come home already, girl!"
Nepgear blinked a few times and Uzume was pleased to see her eyes clearing up and her doubts disappearing. "I'm sorry, you're right, I still have people waiting for me." She stood up and trembled softly. "Hey... Uzume..." She smiled at the redhead. "Thanks."
"Any time, Gearsy." Uzume gave Nepgear a thumbs up.
"As enjoyable as this all is." The other Uzume said as she walked up to them. "What will you do about the stagnation and slow decline of Gamindustri?"
"I don't know." Nepgear said softly. "But I'll work with the others, I'll find a way to make Gamindustri better than it ever was before. I swear it!"
The blue-haired Uzume chuckled and walked off, waving her hands as she disappeared. "Have fun with that, Gearsy. We'll see each other again some day."
"I have so many questions right now." Uzume muttered and looked at Nepgear. "Are you okay?"
"Yeah." Nepgear nodded before wincing and rubbing her cheek. "Except where you hit me, that hurt!" She pouted while Uzume chuckled nervously. "Still, thank you for helping me remember I have people who love me back home."
"I'm sure that your sister and her friends don't blame you, Gearsy." Uzume told her. "Go home and make them proud."
"I will," Nepgear nodded to Uzume. "Thanks."
"Hey, you're the one who killed that Dark CPU with that sword, I could barely scratch that thing." Uzume chuckled softly. "So this is just a small way to pay you back."
Nepgear nodded again and smiled. 'Neptune, Uni, everyone, I miss you all...' She thought to herself and looked at Gehaburn. 'But I'm trying my best, please watch over me.'
I honestly had no plan for this, I just wrote it to write it.