Uma Musume are classified by various genetic traits—such as bay, chestnut, gray, or white coats.
Kitasan Black, for instance, is classified as a bay.
In Japan, there have long been debates—or rather prejudices—regarding these genetic traits. One infamous belief was that "gray-coated Uma Musume are inherently slow."
Of course, this supposed "common knowledge" had long since been shattered by outstanding gray-coated runners like Tamamo Cross, Oguri Cap, and Mejiro McQueen.
A similar prejudice was the notion of "stallions versus mares."
From a biological standpoint, the Uma Musume-related gene was primarily recessive. If a mother was an Uma Musume, the likelihood of her daughter inheriting the trait was significantly higher. With human mothers, it was extremely rare—practically random chance.
Thus, Uma Musume were traditionally classified as either "mare-type" (牝, hinba) or "stallion-type" (牡, boba).
Just like the gray-coat stereotype, the industry and fans had long assumed mare-type Uma Musume were weaker. Many races even restricted entry exclusively to mare-types under the guise of protection.
Despite the presence of impressive mares like Air Groove, dubbed "Empress," and Hishi Amazon, "Heroine of Justice," these prejudices persisted.
Until the emergence of the legendary duo, the "Unmatched Pair."
Both were mare-type Uma Musume, competing in a field dominated by stallion-types at the highest level. The two of them swept nearly every top-tier competition, completely overturning existing prejudices.
Coincidentally, following their success, more and more mare-type Uma Musume emerged with astounding performances, effectively silencing discussions of the stallion-mare divide altogether.
One of these legendary two mares was none other than Daiwa Scarlet, the very Uma Musume Agnes Tachyon had suggested.
Even more importantly, Yasui Makoto was certain through extensive observation and testing that Kitasan Black's ideal racing style was as a front-runner, with stalker as a secondary option.
These two racing styles perfectly aligned with Daiwa Scarlet's own specialties during her career. Faced with such a perfect joint-practice partner, Yasui had no reason whatsoever to refuse.
After accepting Agnes Tachyon's offer and briefly gathering additional details from Tokai Teio, Yasui relayed the good news to Kitasan during afternoon training.
"Daiwa-senpai ish going to run wiv me? That's sho amazhing!"
"…How many times do I have to tell you to finish chewing first? Aren't you worried about choking?"
Watching Kitasan Black's cheeks bulge out like a chipmunk, Yasui shook his head helplessly, then paused thoughtfully.
"Wait a second, Kitasan. You already know Daiwa Scarlet?"
"Mhm… jusht a shec, Twainer, lemme finish eating firsht—"
Gulping down an entire plate of fried rice in no time, Kitasan casually wiped her lips with the back of her hand, about to speak again, when she noticed Yasui sighing and reaching into his pocket for tissues.
"Sometimes I really think you don't act like a girl at all—so sloppy… Hold still, let me wipe your face."
"...Trainer, that was kinda harsh…"
Feeling slightly aggrieved, she protested quietly. But seeing Yasui reach toward her, she suddenly panicked.
"N-No need, Trainer! I-I can do it myself!"
Snatching the tissue packet, Kitasan hurriedly wiped her mouth and hands, then hastily changed the subject.
"Yeah, I actually met Daiwa-senpai a long time ago! She was on the same team as Teio-senpai before she retired, and even after Teio-senpai retired, I often went to watch Daiwa-senpai's races. If she's coming to practice with me, that's really amazing!"
She excitedly bounced in her seat, then tilted her head curiously.
"Oh right, how do you know Daiwa-senpai, Trainer?"
"It's not me who knows her."
Yasui shook his head, explaining, "It was Doctor Tachyon who introduced us."
"Oh, that makes sense," Kitasan realized. "I remember Daiwa-senpai being very close with Tachyon-senpai."
"When Tachyon-senpai suddenly retired, a lot of people online were saying really awful things about her. Tachyon-senpai ignored it all, but Daiwa-senpai was furious—she constantly spoke up to defend her. If Tachyon-senpai arranged this, it makes perfect sense."
Yasui nodded thoughtfully.
He'd vaguely heard about the controversy surrounding Agnes Tachyon's retirement.
Four consecutive wins culminating in the Satsuki Sho—her potential for the Tokyo Yushun (Japanese Derby) and Kikuka Sho was undeniable. But immediately after the Satsuki Sho victory, at the height of her popularity, Tachyon abruptly retired.
The official reason given was superficial flexor tendonitis in her left leg—a troublesome injury for an Uma Musume. While not impossible to heal, full recovery was extremely rare with current medical technology.
Fans struggled to accept this, and malicious rumors—likely instigated by those with ulterior motives—quickly spread, causing significant backlash against Tachyon. Those rumors about "human experimentation" likely originated at that time.
Yet Yasui had been unaware of the behind-the-scenes details, including Daiwa Scarlet's outspoken support. Listening to Kitasan now, he better understood why Tachyon was able to persuade Daiwa Scarlet to help.
"So there was that kind of connection… Either way, it's great news for you."
Reflecting on it briefly, Yasui continued:
"I spoke with President Teio and got some updates on Daiwa Scarlet's current situation. Last year, she completed her second postgraduate degree overseas and is now considering research topics for a PhD in medicine. Probably aiming to follow in Doctor Tachyon's footsteps, I'd imagine."
"Apparently, she's facing a bit of a research bottleneck and wanted a change of scenery. Conveniently, the Academy offered her a temporary job, so she'll be staying here for a while."
"Daiwa-senpai is really amazing, huh?"
Kitasan admired with genuine awe.
"Back at the Academy, Daiwa-senpai was always top of her class. Now she's already finished two master's degrees! She's incredibly smart!"
"By the way, Trainer, what job will she have here? Could it be a school doctor?"
"Not exactly," Yasui shook his head. "She hasn't obtained her medical license yet. Actually, she's coming to replace Fuji Kiseki as the dorm manager at Ritto Dormitory."
"As dorm manager, she'll have daily interactions with active Uma Musume. She probably sees it as an opportunity to collect data for her research. I imagine Daiwa Scarlet is hoping to find inspiration for her doctoral thesis by observing younger, active racers."
"D-Dorm manager?"
Kitasan's eyes widened. "Does that mean we won't see Fuji-senpai around the Academy anymore?"
"No, not really," Yasui reassured her. "According to President Teio, Fuji Kiseki actually applied for advanced training last year. It just took a while to process, and her transfer only recently got approved. She wants to advance her career, after all. You'll still see her around the University Department."
"Oh, I see…" Kitasan nodded understandingly, then brightened again.
"So, from now on, I'll get to see Daiwa-senpai often and practice running together a lot, right?"
"Well, that'll depend on her schedule."
Yasui smiled faintly.
"But President Teio mentioned Daiwa Scarlet will have a lot of free time these next few days while the dorm handover is sorted out. So make sure you're prepared—three days from now, you'll have your first joint practice run with your Daiwa-senpai."