|“||People often liken Strikers as Robbers, and Defenders as Cops. So on my watch I ain't letting no Robbers steal any goals.||”|
Aiku is a tall man with shaggy brown hair with green ends and light facial hair. As a young boy Oliver was a relatively big player and as he got older he got bulkier. His facial structure stayed the same just becoming sharper and more refined and he grew facial hair. Aiku possesses the rare genetic condition, Heterochromia iridum, so his left eye is green and his right eye is purple.
During the Japan National Representative match, Aiku dons the official white with red trim U-20 jersey and shorts and wears the captain's band on his left sleeve. Under that he is wearing a black shirt and gloves. Aiku also wears black cleats with a pink edges.
When Aiku was young he wanted to become the best striker in the world but his coach and other adults tainted his dream with the philosophy of "playing for others". He lost the will to become the best striker in the world in time but decided wholeheartedly to become the best defender in the world to spite all the adults and coaches that told him to play for others and refused to help him pursue his own goals. He promised himself though, that if a "true striker" ever appears, struggling to bloom in Japan, he will do whatever it takes for them to shine and prevent them from being tainted like he was.
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 not to be too worried about woman.
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 Shidou from harming their Ace and also keeping 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 also can 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.
- Libero: The libero (Italian for "free") or sweeper is a more versatile type of defender that sweeps up the ball if the opponent manages to break the defensive line. Their position is rather more fluid than other defenders who mark their designated opponents. Sweepers are usually faster than that of the other players on the team, and are built slightly smaller than the others. The sweeper's ability to read the game is even more vital than for a centre-back; they also are usually confident on the ball and possess good passing and vision, as they are often responsible for starting plays from the back-line.
The key to the Japan U-20's defense is Aiku being more versatile than the other defenders and being able to sweep up the ball or shut down the opposing offense altogether with his iron clad defense.
Professional Football Technique: Aiku is considered to be one of Japan's brightest talents, being the captain of the U-20, as well as already having an offer to play for an unspecified Italian professional club, in the Serie A. A testament to his professional technique is the fact that he went from being a respected centre-forward, to a talented defender almost seamlessly. The entire U-20 team is built with him at its centre, being referred to as the 'Diamond Generation'.
Spatial Awareness: Aiku has an incredibly large field of view, being able to take into account the conditions of every player in front of him. Isagi noted that Aiku was not marking him specifically, yet was able to intercept a pass to him, because he was able to adjudge Isagi's speed, as well as the source of the pass and the positions of every player. This wide field of view enables him to detect any threats to the U-20 goal and react instantly predicting any movements or surprise plays.
Dominant Physicality : Aiku also has an incredible physique which enables him to perform high level plays without issue. His strength was first demonstrated when he physically subdued Ryusei, a notoriously powerful player, without any issue. His strength is also demonstrated in his jumping ability, being able to reach great heights to intercept the ball. In addition to this, Aiku moves across the pitch with incredible speed, being able to sweep up any loose balls and cover defensive holes left by his team, as well as retreat to the center when needed.
Reflex: On top of his high spatial awareness, Aiku also has the reflex to immediately determine where the greatest threat to the goal is and the physical ability to go there without hesitation. It is the combination of this reflex and spatial awareness that makes Aiku such an effective defender, as he not only sees all positions of every player at once, but he also moves immediately (often ahead of the strikers) to intercept the ball.
- Total Defense: By combining all three of these weapons, Aiku is able to predict, react to and intercept any ball played into the defensive third, acting as a critical safeguard in the U-20's defensive line up. It is this ability which makes Aiku the cornerstone of the U-20's 'Diamond Generation'.
Flow State: Flow, as described by Ego, is the state of "total immersion" or "being in the zone". It is the mental state in which a person performing some activity is fully immersed in a feeling of energized focus, full involvement, and enjoyment in the process of the activity.
Aiku managed to enter the Flow state during the match against Blue Lock, in response to Baro and Yukimiya's attack. Whereas normally he reacts to plays as he sees them happening, whilst in flow he can see and even feel the critical points in his team's defense, enabling him to move ahead of the game and cover those weak areas. This state also improves Aiku's one-on-one defending, being able to completely shutdown a player's offense by reading their every possibility and shutting down all their options like he did to Rin but when faced with skill that is above his understanding his defense falls flat without help.
- His favorite player is Virgil van Dijk.
- His favorite season is summer because he gets to see swimsuits.
- His favorite animal is young bird/chick. Seeing lots of chicks is healing to him.
- His favorite manga is Chi: Chikyū no Undō ni Tsuite.
- Blue Lock Manga: Chapter 113.