(I did some digging, and it seems there's no canon material about Yukimura and Sanada joining Rikkai—just that side story with the "Little Demon" entering. So I'll just wing it!)
Kanagawa.
Rikkai Dai Fuzoku Middle School.
Mitsuya Akuto stared gloomily at the tennis club.
After the graduation of Akutsu Hiroshi and the others, he was the only regular left standing.
By all accounts…
Rikkai was about to enter an era of decline.
The thought of Rikkai's downfall beginning under his leadership made Mitsuya's stomach churn.
"Captain, today's new member intake might bring some strong players," said a brown-haired boy with closed eyes.
Mitsuya sighed. "At least I have you, Renji. I'd be completely lost otherwise."
"Yo~ Mitsuya-senpai, finally found you!"
A familiar yet unexpected voice rang out.
Mitsuya and Yanagi turned to see a red-haired boy approaching.
"Mori?!"
"Huh?!"
It was none other than Mori Juushirou—wearing Rikkai's uniform.
"Y-you… transferred?!" Mitsuya stammered in shock.
Mori was Shitenhouji's ace. For him to transfer from Kansai to Kanagawa…
Did Shitenhouji explode or something?!
Mori shrugged. "Family issues forced us to move. Figured I'd join Rikkai while I'm here."
"This is perfect!"
Mitsuya grabbed Mori's shoulders, elated.
With Mori's addition—plus Yanagi—Rikkai wasn't doomed just yet. At the very least, they could still challenge Seigaku.
According to data records, Seigaku only had three regulars left: Yoru, QP, and Yamato.
Yamato would be easy to handle.
With the right strategy, they might even defeat Seigaku and reclaim the Kantō Championship.
That would be Mitsuya's redemption before graduation.
"Renji, spread the word—we're holding the regulars selection matches tomorrow!"
"Tomorrow?!" Yanagi's eyes widened.
---
The announcement sent shockwaves through the club.
Meanwhile, in the training area…
Yukimura Seiichi and Sanada Genichirou, having just finished ball-picking duty, began their daily drills.
"Once we're regulars, we won't have to pick up balls anymore," Sanada muttered darkly.
For them, this menial task was nothing short of humiliation.
"Mhm."
Yukimura smiled. "Luckily, Rikkai allows first-years to compete for regular spots. With seven openings besides Mitsuya-senpai, our chances are good."
"You two seem pretty confident."
A boy with blue-white hair sidled up. "Name's Yagyuu Hiroshi."
Yukimura nodded politely. "Yukimura Seiichi. This is my friend, Sanada Genichirou."
Sanada stayed silent. Outside of Yukimura, he wasn't keen on socializing—especially in unfamiliar territory.
Yagyuu's gaze shifted to a dark-skinned boy nearby. "Foreign exchange student?"
"Nah, that's just my classmate, Jackal Kuwahara," a younger voice cut in. "He's got Latin blood, so he's tanner. I'm Marui Bunta—nice to meet ya!"
And so, the gears of fate began turning at Rikkai.
---
The Next Day.
Rikkai's regular selection matches commenced in full swing.
Four groups competed, with two regular spots per group—even the captain had to participate.
After a full day of intense matches…
Unlike previous years (where losses in the Kantō and Nationals had thinned their ranks), this year's newcomers were anything but weak.
Group A:
Yukimura vs. Yanagi.
Though both had already secured spots, their match was telling.
Within ten minutes, Yanagi's data tennis crumbled.
Nothing he'd gathered on Yukimura worked. His signature techniques were effortlessly returned, and soon, he felt trapped—like no matter what he did, victory was impossible.
By the end, Yanagi was drowning in darkness: unable to see, hear, or feel.
(And this was Yukimura holding back.)
With his health restored and guidance from Yoru, Yukimura's mastery of Perfect Tennis and Insight had reached new heights.
Had he wanted, he could've induced the "Yips" by the second game.
After the match, Yukimura snapped Yanagi out of it—the latter's eyes wide with terror.
Yukimura could only sigh. His natural playstyle and mental pressure made avoiding the Yips nearly impossible.
Group B:
Sanada vs. Mori.
This one was… interesting.
After a few games, Mori forfeited outright—infuriating Sanada.
Having seen Mori's skills at last year's Kantō Tournament, Sanada had craved a real battle. Instead, Mori couldn't be bothered.
(And thus, Sanada's grudge against Mori was born.)
Group C Winners:
Mitsuya Akuto & Jackal Kuwahara.
Group D Winners:
Yagyuu Hiroshi & Marui Bunta.
With this, Rikkai's new lineup was complete—a top-tier, powerhouse roster.
After compiling the data, Mitsuya couldn't hide his excitement.
He'd expected decline, but these first-years were monsters—especially Yukimura and Sanada, whom Yanagi and Mori rated extremely highly.
---
Other schools were thriving too.
Shitenhouji:
Though Mori was gone, they'd gained Shiraishi Kuranosuke, Ishida Gin, Oshitari Kenya, Konjiki Koharu, and Hitouji Yuuji—a massive upgrade.
Yamabuki:
After Nakagauchi's departure, newcomers like Senri Chitose and Minami Kentarou joined.
Shishigaku:
Now boasting Kippei Tachibana and Chitose Senri, they were set for a resurgence.
Sadly…
Mizudori had collapsed after Byoudouin's departure.
New captain Fuwa Shuzo nearly fainted when he saw the remaining "regulars." The only semi-competent player was Monzen Satoru—and even he was mediocre.
Meanwhile, Buchou, Irie, and Kazahaya's schools also declined.
Though their Nationals bronze medal brought some prestige, Maihama Academy failed to attract any standout talents.
---
And so, the new era began.
With Seigaku's dominant Nationals victory fresh in memory…
Every school now had them in their crosshairs.
No longer the challengers, Seigaku stood as the kingdom to overthrow—ready to face all comers in the new season.
---
(A/N: "Mada mada dane" never gets old. )