Pony Training: The Horse Spirit's Lesson
“…???”
Sonia finally pulled out her communication terminal.
In the dimly lit back alleys of Sky City, or in the member-only secret fetish training facilities, or perhaps in the autonomous districts where special races lived, which one might dismiss as a cultural difference. In other words, the 'mares' or 'ponygirls' that everyone called them.
The search results that appeared on Sonia's communication terminal after adult authentication were, as expected, images of that sort.
“Is it... the 'military horse' that the spirit mentioned... this... this... this... side, spirit?”
With a swish, Sonia showed the images that had popped up on her terminal screen to the spirit, her face even redder than her own.
The screen was filled with images of 'mares', 'ponygirls', 'ponies'.
From a normal girl to a clearly slave girl, various women wearing shiny black leather bondage suits, with strange bit gags in their mouths. With decorative donkey ears on their heads, in an odd posture of crawling on all fours like a horse standing on two legs.
It was exactly like a 'bitch' but with dog ears changed to donkey ears.
“Um... Yes, that's it, Sonia! Exactly! Then is preparation ready?”
“This world has mares too! Then I don't need to explain at length?”
“Ah... Mares... huh... ♡”
The image of slave girls in lewd leather bondage suits being led by chokers around their necks made Sonia's body tremble with a thrilling shiver.
Seeing the smooth gloss of the leather on the screen, the humiliated yet ecstatic expressions on the girls' faces, and the saliva flowing from their mouths that couldn't close due to the gag, Sonia's heart pounded violently and her lower belly heated up.
The next Nebulix search tag was set to 'mares', 'ponygirls'.
At the end of being sold to a master with pony fetish and trained, the appearance of a female slave who usually wears bondage suits, just adding a donkey ear headband for cosplay. The spirit drew a line with displeasure, saying that 'mare' and 'military horse' are clearly different.
“Is this not unusual? Such lowly mares who don't even know how to serve their master. Don't worry, Sonia! What you'll learn is not such mares, but a proud military horse! I will help you thoroughly learn special training! ...Or is this world so primitive that there are no mares... or military horses that are specially trained to protect their masters?”
The spirit's explanation about 'military horse' had transformed into a cunning salesman's persuasive pitch, like an enthusiastic salesman whose sales record had recently shrunk.
The words pouring from the small mouth were wrapped in honor and pride, but the essence was a list of extremely vulgar and tenacious desires.
The spirit's explanation contained a power that subtly stimulated the listener's primal desires rather than their rationality.
Nevertheless, the spirit declared that there was an insurmountable gap between the lowly 'mare', i.e., 'ponygirl' that appears in internet search windows, and the honorable and proud 'military horse' she was about to expound.
The confidence and pride accumulated over hundreds of years were evident in every small gesture.
"...There is such a profound difference, Sonia. Have you now clearly understood the difference between the lowly and lewd female slave, the mare, and the proud military horse that carries the master's will and runs across the battlefield? Of course, if you complete the training as a military horse perfectly! If this body, the horse spirit, recognizes that you have completed the training to the point of perfection, then the 'military horse special ability' that leads to the iron-like physical strength as a military horse and the power that no one can ignore will naturally be passed on to you, Sonia! How about it, Sonia. It's definitely not a loss, right?"
"Uh... um... It's really different..."
Sonia reluctantly nodded her head at the spirit's passionate explanation. In fact, Sonia's ears didn't properly hear the subtle difference between 'sex slave' and 'military horse'.
Only words like 'mare', 'training', 'passed on' that implied forbidden pleasures stuck in her mind, making her heart beat uncontrollably fast.
Anyway, after returning to the spirit world, she might be called again at any time.
In the fantasy world over there, despite claims of being summoned as guardian spirits for generations, Sonia saw it as a highly perverted successor of bondage fetish, turning innocent girls of ancient noble families into 'mares' and subjecting them to her own vulgar special training.
No matter what bizarre story there was, she had been abandoned in a dungeon and became Luce's trophy, eventually flowing into the rusty medal containing the spirit.
Since she was returning to a state close to extinction, it was a pity that her existence proof, the 'military horse special ability', would disappear from the world.
For the remaining short time, it was a proposal to pass on that unique ability that gives permanent bonuses to sturdy physique and strong power.
The target of the proposal was the D-class hero in Sky City, Sonia, who had only wiped the rusty medal with a cloth.
Special ability. Unique abilities obtained through special opportunities different from the small but important stats that rise with level up. It could sometimes become a powerful force that shakes the world.
Sonia also had a few such special abilities. For example, 'special ability to not shrink tongue when eating potato chips' which she unconsciously acquired because she ate more potato chips than rice, or 'special ability to pour cola without overflowing', which didn't help in survival.
Of course, there were small and strange special abilities like 'accurately matching seasoning when cooking' or 'opening the desired book page at once'.
The horse spirit's promise was on a different level. Permanent boost to core stats that are fundamental to all battles and universally acclaimed: strength and stamina. 'Military horse special ability'. Sonia had no reason to refuse the sweet temptation that even just learning it makes you stronger.
(Gu... military horse... turning into female slaves... innocent girls... ugh... my heart... my heart is beating too fast... ♡ This opportunity... I might never have again... ♡)
Sonia's heart was violently surging. Although she didn't know exactly what a military horse was, the process started with becoming 'mare' state, and the spirit's explanation that through special education, awareness as a military horse is instilled.
It was an opportunity that anyone would covet, attractive enough in itself.
What made Sonia's heart race madly was the image of 'female slave', i.e., ponygirl.

The shiny black leather corset tightly squeezing the waist as if breaking it, the protruding nipples exposed with cold metal rings and piercings still attached.
Leather boots climbing up the firm thighs honed by training. The metal choker, evidence of the slave who has given up freedom. Wearing all that, with a soft silicone gag lightly in her mouth, the lewd fetish slave image.
Kukuk... ♥
From the moment she recalled this image, or rather, from the moment she thought of her own unique 'opportunity' that doesn't come easily to others, there was no choice for refusal in Sonia's heart.
Rather, she was full of impatience to start the training as soon as possible. The flushed cheeks and rapidly breathing were the evidence.
“I... I will ask for it too, spirit! I don't know much yet... so... please take care of me!”
In a trembling voice as if excited, Sonia pleaded. The spirit's face lit up at that sight.
“Hooh... Even though I intruded on Sonia's home like this and received a meal... and even fulfilled my personal desire-filled request... I'm really grateful, Sonia! Since it's come to this, I will pass on the perfect military horse special ability with everything I have, Sonia!”
The fact that before disappearing, she could leave behind a clear trace of her existence, the 'military horse special ability', made the spirit happy alone and floated around the living room.
“I may have already noticed, but just by dropping this body, the medium, into sweet black water and scrubbing it vigorously! This way, the real me won't appear, Sonia.”
“Then how did you appear?”
Sonia, who hadn't realized at all, asked innocently, and the spirit reached her small hand into the carrot basket again, as if the big problem was over.
The spirit explained that not everything as a mare could receive the master's choice, i.e., 'selection', to receive military horse training.
The sturdy body trained as a hero and the beautiful body line that can proudly show as a military horse in front of others. Sonia was the talent bestowed by heaven, perfectly satisfying all those qualifications.
“Ultimately, obtaining the military horse special ability as a military horse means becoming my successor. That is, one must go from person to mare, from mare to military horse. Of course, with me here, there's no need to worry!”
“Crh... Originally, one would need to swear an oath of soul to shake the world as a military horse for life... but... glance... sneak...”
The spirit glanced at Sonia's reaction.