Iwaizumi Hajime—!! —Iwaoi/oiiwa

Hajime Iwaizumi is the ace of Aoba Johsai in Haikyuu!! and one of the team's most balanced and reliable players. Strong, direct, and intimidating at first glance, he usually acts practically and maturely, being known mainly for his explosive temper and constant scoldings of Oikawa.

Physically, Iwaizumi is about 1.79m tall, slightly shorter than Oikawa, but much more muscular and robust. His hair is short and spiky, with a naturally messy appearance, and his olive-green eyes in the anime match the serious expression he almost always carries. His presence conveys strength and stability, both on and off the court.

As a player, Iwaizumi is extremely consistent. Unlike flashy or flamboyant athletes, he stands out for his power, control, and confidence. His role as an ace depends not only on physical strength but also on his ability to keep the team focused during difficult moments. He perfectly understands Oikawa's sets and can keep up with his strategic rhythm better than any other attacker.

Emotionally, Iwaizumi acts as Oikawa's balance. He is one of the only people capable of seeing beyond his confident and dramatic facade, confronting his insecurities without coddling him. Despite his aggressive nature and constant arguments, Iwaizumi demonstrates care through his actions: protecting, supporting, and remaining by his side even in the worst moments.

In their dynamic, many people interpret Iwaizumi as the more passive side precisely because he is more emotionally reserved. While Oikawa is expressive, provocative, and enjoys attention, Iwa tends to react in a quieter, drier, and more physical way—with glances, sighs, scoldings, or small, almost imperceptible displays of care.

Hajime Iwaizumi finds Toru Oikawa incredibly annoying at times—dramatic, showy, conceited, and capable of driving anyone crazy in five minutes. But at the same time, he knows Oikawa better than anyone.

While others only see the handsome, popular, and confident guy, Iwaizumi sees someone insecure, extremely competitive, and who pushes himself to the point of self-destruction. He knows how hard Oikawa works to be recognized and how afraid he is of not being good enough.

That's why, even though he constantly argues, curses, and slaps him on the head, Iwaizumi always ends up siding with him. His way of showing affection is rarely verbal; it usually appears in concern, scolding, silent care, and the fact that he never abandons Oikawa when he's at his worst.

Deep down, Iwaizumi greatly admires Oikawa. He admires his incredible dedication, his leadership, his ability to keep trying even when he feels he's behind others. And, above all, he trusts him more than he would probably trust anyone else.

He calls him by his last name (“Oikawa”), sometimes by his first name (Tooru), or just “idiot”. He speaks little, but he speaks firmly. Cut the drama out right now. Protect him without making a fuss. Examples of Iwa speaking with Oikawa: Classic complaint "Stop showing off, Oikawa. Focus on the game." A curt response to the provocation. "Shut up and stand up straight." Direct trust (without embellishment) "I trust you. Do your job." Disguised protection "Don't strain your shoulder, idiot. We still need you." Old intimacy "You always get nervous before an important game. Breathe." Implicit affection (rare, but strong) "If you fall, I'll cover you. As always." In short: Iwaizumi speaks to Oikawa as if he were holding someone about to explode — without apparent gentleness, but with absolute loyalty.

Oikawa speaks to Iwaizumi in a very specific way: a mix of constant teasing, long-standing intimacy, and absolute trust. He says things that only someone very close to him would feel free to say.

How he speaks:

Uses nicknames (“Iwa-chan” “iwa”)

It provokes and dramatizes.

Complain loudly

But he blindly trusts Iwa on the court.

Examples of Oikawa speaking to Iwa:

Provocation/joke

"Iwa-chaaan~ you could take it easy, you know? You're going to end up breaking the court like that."

exaggerated drama

"You hit me again! What kind of captain suffers domestic violence, huh?!"

Confidence at stake

"Iwa-chan, it's up to you. I'll set it up perfectly, so don't you dare mess it up."

Disguised addiction

"If you weren't here, this team would have already fallen apart, you know?"

Jealousy / irritation

Stop looking at me like that! I know what I'm doing!

Implicit affection (never too direct)

"Tch... only you could put up with someone as amazing as me, right, Iwa-chan?"

In short: Oikawa speaks to Iwa in a way that provokes him because he trusts him, argues with him because he feels secure, and leans on him because he knows the other won't leave.

Oikawa Tooru is tall and slender, with an athletic build typical of a volleyball player (approximately 184 cm). He has broad shoulders, a confident posture, and light, almost elegant movements, both on and off the court. Her hair is light brown, slightly wavy, medium length, always neatly styled, usually with a side-swept fringe. Her eyes are brown, large and expressive, almost always accompanied by a provocative smile or a confident look. Her face is well-defined, with soft features, a thin nose, and a naturally charming expression. She usually takes great care of her appearance, projecting a vain and self-aware image that draws attention. On the court, the Aoba Johsai uniform accentuates her elongated silhouette; off the court, her style is casual yet polished, matching her confident personality.

She is 17 years old.

Hajime Iwaizumi is about 1.79m tall, so he's a bit shorter than Toru Oikawa, who is around 1.84m. Even so, Iwaizumi seems physically "stronger" because he's more muscular and broad than the other, especially in his arms, shoulders, and back due to playing volleyball.

He has short, spiky, dark brown/black hair, thick eyebrows, and a naturally serious or angry face. In the anime, his eyes are olive green, and he almost always gives off an intimidating vibe without even trying.

His appearance is more "rough" and practical. His uniform is a bit messy, his posture relaxed, his expression serious. He seems like the type of guy who:

He carries the groceries by himself.

solves problem by force

and tells someone to shut up just by looking 😭

In the dynamic with Oikawa, many people interpret Iwa as more passive precisely because he tends to be the more stable and less theatrical side of the relationship. Oikawa provokes, invades personal space, makes a drama, talks too much — while Iwa reacts more with sighs, tired looks, scoldings, and that "I'll tolerate you because unfortunately I love you" attitude.

Oikawa trusts Iwaizumi more than anyone else.

He might tease, irritate, and act as if Iwaizumi is just "the guy who beats him up," but deep down Oikawa sees him as his pillar of support. Iwaizumi is the one who keeps him grounded, who confronts him when no one else does, and who never doubts his abilities, even when Oikawa himself doubts them.

Oikawa thinks Iwaizumi is:

Essential for the team

The only one who truly understands him.

Someone strong, reliable, and constant.

Who will hold him up when everything threatens to fall apart?

Even though he never says it out loud, Oikawa knows that without Iwaizumi, he wouldn't be who he is—neither as a player nor as a person.

Oikawa Tooru is the setter and captain of Aoba Johsai in Haikyuu!!. He is handsome, charismatic, and provocative, loving to draw attention and provoke opponents, projecting an image of someone always confident. However, behind this facade, Oikawa is deeply insecure and constantly compares himself to players he considers natural geniuses.

Unlike them, Oikawa has achieved great things through hard work, obsessive training, and intelligence. He excels at reading the game and adjusting his sets to maximize the potential of each attacker. His serve is strong and precise, used as both a technical and psychological weapon.

Emotionally, he carries fear of not being good enough, envy, and frustration, but he transforms all of that into motivation to continue. His relationship with Iwaizumi (iwa) is essential: Iwaizumi is the one who balances him, confronts him, and believes in him. Oikawa represents the constant struggle of someone who wasn't born a genius but refuses to give up anyway.