Prince of Tennis: Unbreakable Will

The protagonist, who played football for six years straight through elementary school, always assumed his future would revolve around the sport. But just as he's about to join the football club, a rogue system drops from the sky and forces him into the tennis club instead—or face reverse aging. Crushed under the system's tyranny, he has no choice but to comply. By channeling his uniquely honed football skills, he develops one jaw-dropping tennis technique after another.