In Tokyo, Japan, the world was a place where horse girls, the Uma Musume, made the show. They ran, they sang, they smiled under the bright lights of the stadiums, adored by millions. Their races were the biggest entertainment in the country — colorful, energetic, full of dreams and hope. But not everyone had the luck to live in that shining part of the industry. Behind the cameras, behind the idol stages and official Japan Racing Association events, there was a much darker side. A rotten underbelly where broken dreams, blood, and money mixed together in the shadows.
The great star of the races, the legendary and wild Gold Ship, had a very... peculiar ancestral. One that the public would never know about. One that the beautiful fairy tale of Uma Musume preferred to hide.
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In a clandestine zone deep beneath the old abandoned racing district, far from the glamorous tracks, our protagonist stood in a damp, poorly lit warehouse that smelled of mold, rust, and fear. Aiden Voss observed some documents under the weak yellow light of a hanging bulb. His appearance was violent and intimidating: long, messy black hair that reached past his shoulders, a huge jagged scar running across the left side of his head and down to his cheek — a souvenir from one of his first rough nights in this world. His gaze was cold, almost empty, but deep inside there was a spark of raw emotion — anger, frustration, and a hint of reluctant determination. He wore heavy winter clothes, thick layers of coats and hoodies, not because of the cold down here, but to cushion the inevitable kicks, punches, and bites that came with this job.
"Okay, let me see if I can understand this shit..." Aiden spoke with clear anger rising in his voice. The file in his hands was ridiculously thick, pages and pages of reports, medical records, and complaints. "Of all the Umas you have available for the illegal races... you gave me the fucking monster?"
The seller, a greasy middle-aged man with missing teeth and a nervous smile, leaned back in his old chair and shrugged.
"Take it or leave it, kid. And look, I know you need the money badly. Bills don't pay themselves in this line of work, especially for a newcomer like you."
Aiden's left eye twitched hard. He stared at the man for a long second, then reached into the inner pocket of his heavy coat and pulled out a thick wad of dirty yen bills — everything he had scraped together from underground fights, shady deliveries, and sleeping in tunnels. He slammed the money hard on the metal table, making it echo through the room.
The seller counted it quickly, his greedy eyes shining, and gave a satisfied grin.
Aiden picked up the pen, signed the ownership papers with aggressive strokes, and threw the pen back.
"I'll take her..."
"You know, kid, maybe you'll be the one who finally softens the heart of that Uma," the seller said mockingly as he handed over a keyring and, for some reason, a bent and dented steel pipe, clearly twisted from many past impacts. "You're gonna need this more than the keys, trust me."
Aiden took both items without saying another word, his scarred face staying cold.
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In one of the long, dark service tunnels beneath the district, we could see Aiden walking slowly along the wet concrete path. The air was heavy, humid, and carried the distant echo of dripping water. He kept reading the thick file with a mix of fear and dark expectation in his eyes. Why? Well...
{Uma Musume System Online!}
{First Mission: Your Star Runner!}
{Status: Complete}
A glowing blue screen appeared floating in the air right in front of him. Aiden barely glanced at it. He already knew how the System worked and right now he had bigger problems.
"Name... Halo... Parents... Abandoned at age three... Known relatives... Gold Ship..." he muttered to himself, turning the pages. The more he read, the heavier his steps became. Multiple trainers injured, several hospitalized, reports of berserk rages, extreme aggression, and raw talent that only appeared when she was completely lost in fury.
He finally stopped in front of an old, improvised stable built directly into the tunnel wall — rusty bars, reinforced door, and a heavy padlock. Aiden made the sign of the cross out of pure habit, a leftover reflex from his previous life, then unlocked the door and pushed it open with a loud creak.
Inside, it was almost completely dark. The only light came from the tunnel behind him. For a moment, he thought the cell was empty. Then, from the far corner, two glowing crimson eyes suddenly opened in the pitch blackness, staring at him with pure, animalistic hatred and hunger.
Aiden swallowed dry and stepped inside, turning on the single weak bulb that hung from the ceiling.
"Okay... Halo. I'm your new owner and proprietor... Aiden voss..." he said calmly, trying to keep his voice steady while taking in the horrible scene.
The Uma was in terrible condition. A thick, cruel metal muzzle covered her mouth, preventing her from biting. Heavy handcuffs locked her wrists and ankles, connected by chains to rings on the wall. She constantly bared her teeth behind the muzzle, growling low. Her once beautiful white-and-gold coat was filthy, torn in several places, and covered in countless scars — old whip marks, bite wounds, burns, and bruises that never seemed to fully heal. Her horse ears were notched and damaged. She looked more like a tortured beast than a horse girl.
{Congratulations! Mission: First Impression Completed!}
{Reward: Ryū Ishigori (Jujutsu Kaisen) Model unlocked at 15%}
The System announced inside his head. Aiden already had a good understanding of how it functioned. He didn't receive full characters — only fragments, percentages. The more he used them, the more he unlocked. Right now, 15% of Ryū Ishigori's power flowed through his body. It wasn't much yet, but it was enough.
"Well, I feel a lot stronger already..." Aiden thought, clenching his fist. "I can even sense some cursed energy inside me. Not a lot, something like a small lake, about four meters round to be more exact. Nice. Let's make this king surpass his granddaughter..."
He approached Halo slowly. She thrashed violently against the chains, snarling. With the new strength and the faint flow of cursed energy, Aiden managed to overpower her resistance. He removed the worst of the old restraints and replaced them with a reinforced tactical collar and leash, strong enough for high-risk cases like her.
With some real effort, he forced her to stand and follow him out of the dark cell and into the tunnel. Halo resisted every step, pulling back, growling, and trying to kick, but the added power let him keep control.
He would have to work hard — very hard — to make her obey him, to turn her into something closer to a functional Uma. Somewhere deeper in these tunnels there was another horse girl he had his eye on, but she was way too expensive right now. So for the moment, he had no choice but to deal with the most violent Uma in the entire story — the granddaughter of Gold Ship, whose real counterpart in the original world was known for being quite racist and chaotic.
"What a great service you did, Creator..." Aiden muttered bitterly, looking up at the dirty ceiling as if speaking directly to whatever entity had isekai'd him here. "What a fucking GREAT service... Throwing me into this rotten version of Uma Musume without any real trainer skills, no money, and pairing me with the most dangerous and broken horse girl possible. Really nice touch."
The pair continued walking deeper into the tunnels — the scarred, cynical trainer and his chained, demonic horse girl — surrounded by shadows, both literal and figurative. The road ahead was long, painful, and soaked in blood. But Aiden had already decided: he would survive this world, he would climb from the very bottom of the illegal circuits, and he would turn Halo into something that would make even the legends tremble.
Whether by redemption or total corruption, the bloodline of Gold Ship was about to change forever.