Elmer Siegfried, the German U-17 tennis team’s middle school representative, commands attention with his striking blend of feminine and masculine facial features and a bold hairstyle. Arrogant and defiant in defeat, he dismissively grabs Tezuka’s face during a strategy debate and refuses Fuji’s post-match handshake after losing a pre-World Cup doubles exhibition. This humiliation fuels his vow for revenge, though he remains sidelined through much of the tournament.

Partnered with Michael Bismarck in a pre-tournament clash against Japan’s Duke Watanabe and Fuji, Siegfried endures Duke’s explosive "Duke Homerun," which hurls him into the stands. Temporarily benched by Bismarck, he later attempts a tactical smash but pivots to a cross volley upon spotting Fuji’s defensive stance, revealing his knack for exploiting weaknesses. Despite these maneuvers, the German duo falls 5-7. Fuji’s match-sealing "Hakuryuu" deepens Siegfried’s resentment toward the Japanese team, hardening his resolve for retaliation.

A right-handed serve-and-volley specialist, Siegfried relentlessly targets opponents’ errors and vulnerabilities. Though his techniques lack polish, his sharp observational skills and adaptability during matches compensate, aligning with his reputation for gritty perseverance.

His rivalry with Tezuka drives his competitive evolution. Outside tennis, Siegfried enjoys carpentry, verbal sparring, and leisurely strolls, adores gold trinkets, gummy bears, and Christmas markets, and openly seeks a girlfriend—all while despising tire-shaped gummies. His name, rooted in Germanic terms for "victory" and "peace," mirrors his national pride and unyielding ambition.

In the U-17 World Cup semi-finals, reuniting with Bismarck against Japan’s Tanegashima and Kirihara, Siegfried suffers another narrow defeat (5-7, 7-6, 7-6), cementing his recurring struggle to conquer Japanese rivals despite his fierce determination.