Aizawa Suguru is a genius midfielder, captain of the school soccer team, who even starred in the U-15 team for Japan. He is expected by many to shoulder the future of Japan's football world. He is aware of little brother's talent as a soccer player and is irritated of Kakeru's lack of motivation.

Spoiler

In Volume 2 Suguru has an accident and because his brother is on the verge of dying he donates his heart, because he knows he won't live any longer. Also when he gives his heart to Kakeru, he also gives his dream of winning the world cup.

(Source: Japanese Wikipedia)