★| Oliver Aiku— BLLK

Oliver Aiku (オリヴァ・愛空アイク, Oriva Aiku?) is the captain and center-back of the Japan U-20 team. He played as a center-back for Italy's Ubers during the Neo Egoist League

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 stayed the same, just becoming sharper and more refined as he grew facial hair. 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, his right eye's color was changed to blue.

Aiku has been shown to be a womanizer when he invited two girls to karaoke on a date when they did not know about each other. They slapped him and left because of his rudeness, assuming they would want to share him, but he seems to not be too worried about women.

Aiku lives up to his title as captain as he is the defender and peacekeeper of the Japan U-20 team and its players, as seen when he stops Ryusei Shido from harming their Ace and also keeps their Ace and other members in check with his charisma. Despite his seemingly jovial and friendly manner, Aiku changes dramatically when on the field, becoming a dangerous and highly skilled threat. Aiku can be a bit reckless, for he unnecessarily bet the fate of him and his team for a chance to beat the Blue Lock Eleven properly and prove something to himself. When the first half of the Japan National Representative is over, Aiku apologizes to his team for his recklessness and decides to play their trump card to prevent them from losing. Aiku can also be quite blunt; at halftime during the Japan National Representative match, he states that he wanted to see how strong the team was and tells the team that they're "weak" compared to the talented players at Blue Lock.

Aiku is not above showing his respect for those who have impressed him, as he constantly commented on Blue Lock's ability during the U-20 match and when he congratulated and shook Yoichi Isagi's hand at the end of the match for beating him and scoring an incredible goal. After the game, he seems to have no hard feelings but keeps his competitive nature.