Disclaimer: I don't own the Dragon Ball franchise or it's related concepts and characters, but Akira Toriyama and his affiliates do.
The Space Cop
Onboard the Big Gete Star, Solar System of Planet Luud, Age 775
In the thirty-eight years since Planet Vegeta's destruction, Kakarot's Attack Ball came into contact with the legendary Big Gete Star which he then symbiotically linked himself to. Acquiring greater knowledge, the then three-year-old Saiyan then made it his priority to save as much of his fellow survivors as he could and avenge their near extinction on Frieza's empire. During these years, Kakarot allied himself with the Galactic Patrol with the intent of providing a new and secure home world for his race without getting on every intergalactic civilization's bad side as well finding kindred spirits in the people of Planet Earth, whom he had protected on numerous occasions. In the year following Majin Buu's impromptu release, in fact, Kakarot spent his time on an endeavor in restoring a New Type Android's memories.
"Okay, 21, I think this should work." Kakarot said with a comforting smile as he willed wires from the Big Gete Star to cover Android 21.
Thinking they had time to work on 21's memory issues before they could investigate the budding cult on the arid Planet Luud as the Galactic Patrol requested, Kakarot intended to absorb her excess energy reserves which would theoretically keep her more malicious personality at bay enough for the Star's technology to "boot up" her memory. It didn't have a complete guarantee of success, but compared to any other options they had at the moment, it promised the less risks to 21.
"I appreciate what you're trying to do, Kakarot, but we don't have to do this now." 21 suggested with uncertainty before explaining. "As much as I want to get my memories back, I think we should deal with the Luud Cult first."
Smiling in understanding at 21's selflessness, Kakarot replied. "Don't worry, 21. Those morons aren't going anywhere anytime soon." Then hugging 21 and sharing a kiss with her, Kakarot then said. "This will be quick and painless, I promise."
Smiling in acceptance, 21 then allowed herself for Kakarot to absorb some of her power through the wires. By the time it stopped, she felt exhausted and close to unconsciousness before Kakarot then used the wires to interact with her altered body until she then finally started to remember everything about herself. Her family, her very name, and everything in between was known to her at last. Once Kakarot stopped, 21's eyes gave way to tears of joy and sadness all together.
"21, are you okay?" Kakarot asked in concern. "Did it even work?"
Nodding, 21 responded. "I remember everything, Kakarot. But I also remembered that my husband and son are both dead."
Feeling bittersweet as well, Kakarot brought the sobbing Android in his embrace, determined to let her tears all out.
Almost made this directly based on Brainiac's appearance in Injustice 2 before remembering that I hadn't interpreted Goku as a Galactic Patroller until now. I know that Super's ending conflicts with the events in GT, but please remember that there's a movie coming out eventually which might clear the board in time for GT. I know GT wasn't exactly a popular series for whatever reason, but I liked it well enough and would like to write a Dragon Ball fanfiction series that includes it, so to speak. Besides, does anyone really appreciate the thought that a tyrant like Frieza is still at large?
Also, before I start writing about Dragon Ball in a full length setting, can I hear some thoughts about Goku/Kakarot's potential as a harem protagonist? I know harems are "controversial" somewhat in fanfiction, but I plan to make my future full-length One Piece, Code Geass, and Fairy Tail stories with harems for the central protagonists. Nothing too massive, just twelve ladies in a harem per story, but I'm kind of at a blank for stories like Dragon Ball and Naruto which eventually feature "canon shipping" and the children to go with it. Therefore, I'd like to ask the fans on who Goku/Kakarot could pair with other than Chi-Chi in harem story, excluding ladies who marry with kids in canon like Bulma and Android 18 and absolutely no gender bending, but present a plausible reason why no original character children exist because I'm not sure I'd be good at making such OCs and keeping them relevant.
Give it some thought.