Hermann Kaltz is a German youth soccer player who appears as a key member of the West German national team during the Junior Youth Arc. He primarily plays as a defensive midfielder, known for his tactical intelligence and relentless work rate, which have earned him nicknames such as the Workman or the Schemer. Physically, Kaltz is depicted as a relatively short but robust player, and his most distinctive visual trait is the toothpick he constantly keeps in his mouth, only removing it when a situation becomes truly serious.

Prior to the events of the international tournament, Kaltz was already an established player for Hamburger SV's youth team. Alongside star striker Karl Heinz Schneider and the formidable goalkeeper Genzo Wakabayashi, he helped make Hamburg the number one youth team in West Germany. This background establishes him as a player accustomed to high-level competition and success.

In terms of personality, Kaltz often appears laid-back or even lazy, sometimes standing around doing little during matches when he feels his team is in control. However, this casual demeanor is deceptive. He is an extremely cunning and tricky player who becomes highly industrious and effective in critical moments. Wakabayashi, his teammate, notes that Kaltz is unpredictable, and it is impossible to know what he will do when he becomes serious. This shift in intensity is often signaled by him spitting out his trademark toothpick.

Kaltz's role in the story is that of Germany's strategic linchpin in the midfield. While Schneider is the team's offensive ace and captain, Kaltz is the player who disrupts the opponent's build-up, intercepts passes, and links the defense with the attack. In the final match against Japan, he becomes a major threat, showcasing a complete change in his playing style that makes him a key figure in Germany's offensive pushes. His primary motivation is victory, and he is driven by his pride as a German player, becoming fiercely determined when that pride is wounded on the field.

Kaltz shares crucial relationships with his two most famous compatriots. He has a close friendship with Karl Heinz Schneider, born from their long history as teammates at Hamburg. This understanding allows them to combine effectively, as seen when they exchange passes to score the opening goal against Japan. He is also friends with Genzo Wakabayashi, another Hamburg teammate. The two maintain a strong relationship at the club level, and during the national team final, Kaltz is one of the players Wakabayashi explicitly notes as being unpredictable in his actions.

Throughout the Junior Youth Arc, Kaltz shows a clear development in his approach to matches. In the early friendly against Japan, he and his team initially hold back before deciding to play seriously. This tendency to underestimate opponents persists into the tournament semifinal against Uruguay, where he admits to himself that he is at ease and does little in the second half. However, by the final against Japan, he discards this complacency entirely. He becomes intensely focused, engaging in fierce tackles, reading the game at a high speed, and trying innovative techniques to score, showing significant growth as a true competitor.

Kaltz possesses several notable abilities that make him a formidable midfielder. His primary strength is his reading of the game, allowing him to cut passing lanes and steal the ball from opposing playmakers. He is also a skilled dribbler, using a technique known as the Hedgehog Dribble to power his way past opponents. Furthermore, he is capable of attempting spectacular shots, such as a Loop Shot designed to arc over the goalkeeper, demonstrating that he is not just a defensive player but can contribute to scoring chances as well.