Oliver Aiku.

Aiku is a very tall and muscular young man with shaggy dark purple hair with lime green tips and short facial hair. As a child, his facial structure remained the same, only becoming sharper and more refined as his facial hair grew out. Aiku is heterochromatic and his eyes are different colors, with his left eye being green and his right eye being purple. However, in the anime, the color of his right eye was changed to blue.

During the Japan national team match, Aiku wears the official U-20 national team jersey and shorts, which are white with red trim, and wears the captain's armband on his left sleeve. Underneath, he wears a black jersey and gloves. Aiku also wears black cleats with red trim.

When Aiku was a child, he wanted to become the best striker in the world, but his coach and other adults tarnished his dream with the philosophy of "playing for others." Over time, he lost the will to become the best striker in the world, but he wholeheartedly decided to become the best defender in the world to spite all the adults and coaches who told him to play for others and refused to help him achieve his own goals. However, he promised himself that if a "true striker" who was struggling to blossom ever appeared in Japan, he would do whatever it took to make him shine and prevent him from being tarnished like him.

Aiku has been shown to be a womanizer when he invited two girls to karaoke on a date where they didn't know each other. They slapped him and left due to his rudeness, assuming they would want to share him, but he doesn't seem to be too concerned with women.

Aiku lives up to his title of captain, as he is the defender and peacemaker of the Japanese U-20 team and its players, as seen when he prevents Ryusei Shido from hurting his Ace and also keeps his Ace and other members in line with his charisma. Despite his apparent attitude,