[A naturally sweet-looking protagonist with a hidden dark side]
Suzuki Koichi is Suzuki Sonoko's younger brother. He's loved tennis ever since he was born.
With lofty ambitions, he was determined to become a champion before inheriting the family business.
Since he was aiming for the top, he had to attend a middle school with the potential to become a champion.
After looking through the prestigious tennis schools in Tokyo, he was surprised to find that only one seemed to have championship potential: Rikkai University Affiliated Junior High.
Koichi rubbed his chin and thought for a moment, then resolutely gave up on Teitan Junior High, where his sister Suzuki Sonoko studied, and chose Rikkai instead.
He swore to the System that he simply loved playing tennis, and wasn't doing it to get away from the older guy who was always recommending Sherlock Holmes to him. Definitely not.
He just didn't want a Sherlock Holmes fanatic with great theoretical advice but mediocre actual skills bothering him while he played tennis.
Yeah. That's all...
There, he met the Son of God, Yukimura Seiichi; the Emperor, Sanada Genichiro; the strategist, Yanagi Renji; the trickster, Niou Masaharu; the gentleman, Yagyuu Hiroshi; the little sea devil, Kirihara Akaya; the volleying genius, Marui Bunta; and Kuwahara Jackal, who had four lungs.
Together with the Rikkai tennis team, he got everyone in junior high and high school tennis to compete in an arms race. Amid all the feverish competition, he rose to become the King of Overachievers, and won the historic titles he'd promised his friends: sixteen consecutive Kanto championships and three consecutive national championships.
P.S.
★ The protagonist was born with a System. His high level of skill comes from both being immersed in the System's influence from childhood and his own passion for tennis, not from relying on the System alone.
Theme: A passionate young man hones himself and eventually becomes an elite player.