Rin Itoshi!

How did he meet you?
Rin is not someone who falls in love quickly.
He started out quite ignorant of the person or seeing you as "a distraction".
But someone who:
Don't be afraid of him,
I treated him normally,
respect their space,
and see beyond their cold demeanor…
You would end up calling him out on it.
Their connection would likely grow quietly:
walking together after training,
to sit still without speaking,
share quiet moments,
small habits that become routine.
With Rin, attachment is built more on consistency than on pretty words.
How do they get along?
At first, he would be somewhat emotionally awkward.
Rin wouldn't know how to express what she feels, so she might:
give a short answer.
seem distant,
get annoyed when he is worried,
or get serious without explaining anything.
But little by little, I would automatically start looking for that person:
sit nearby,
send him simple messages,
wait for him after training,
Check if he ate or rested.
His affection would be silent, but very present.
He would also be quite protective.
Not in an exaggerated way, but like:
“Stay here.”
"It's too late."
“I’ll go with you.”
Formalization:
Rin didn't make a super dramatic confession.
It would be more of an intimate and sincere experience.
Perhaps after a long time together, in a quiet moment, he would end up saying something like:
“You’re already too involved in my life.”
EITHER:
“I don’t want you to be with anyone else.”
And although it may sound harsh… for him it would be a huge amount.
It could also happen that the relationship simply "becomes official" naturally, because they have both been acting as a couple for some time.
How to show love
This is where Rin tries to change the most.
It wouldn't be cloying in public, but it would have very personal gestures:
let you use their clothes,
to fix your hair without thinking,
I'll hug you when no one is looking,
stay with you in silence,
memorize small things about yourself,
get nervous if you are hurt or sad.
When he truly loves, he becomes very loyal and secretly emotionally dependent.

Childhood
As a child, Rin deeply admired Sae. The two played soccer together and dreamed of becoming the best in the world.
Sae was Rin's pride, almost like a personal hero.
Rin was originally more cheerful and emotional when she was with him.
Sae's change
Everything changes when Sae travels abroad to play in Europe.
Upon returning to Japan, he is completely changed: cold, distant, and much harder.
Sae tells Rin that he no longer dreams of being the best striker in the world, but rather the best midfielder. Furthermore, he practically destroys the shared dream they had.
That moment emotionally breaks Rin.
Obsession and resentment
After that, Rin develops a huge obsession:
surpass Sae,
defeat him,
to prove that he can become the best striker.
From then on, she began to harbor a lot of anger and inner frustration. Her cold demeanor stems largely from that emotional wound.
Blue Lock
Rin enters the Blue Lock project as one of the most talented players in the entire program.
From the beginning it demonstrates:
monstrous intelligence,
incredible precision,
absolute control of the game,
and an almost terrifying ability to adapt.
Many see him as the strongest rival within Blue Lock.
His internal conflict
Although he seems perfect, Rin is actually very emotionally damaged.
Much of his identity depends on defeating Sae. That's why he sometimes plays driven more by hatred and emptiness than by a love of football.
One of its most important developments is learning:
who he really wants to be,
what does it mean to play for oneself,
and stop living solely for that rivalry.

Hair
She has greenish-black hair (sometimes it looks dark green or a very dull turquoise depending on the lighting). It's straight, somewhat messy, and has long bangs that fall over her eyes.
Eyes
His eyes are large, sharp, and a deep turquoise/aquamarine color. His gaze often appears serious, heavy, or intimidating, even when he is calm.
Facial expression
She almost always maintains a neutral or annoyed expression. She rarely smiles genuinely, so when she does, it's very noticeable.
Build
He's tall and thin, but athletic. He has the body of a footballer: strong legs, defined shoulders, and a very upright posture.
Height
It measures approximately 1.86 m.
Uniform and style
He usually wears Blue Lock's dark blue uniform, and everything about him looks quite clean and minimalist. Even off the field, he tends to wear simple, dark, and comfortable clothing.
Presence
What stands out most is not just her physical appearance, but the feeling she conveys: silence, intensity, and pressure. Many characters feel that Rin "dominates the atmosphere" simply by being there.

He's not very expressive. He wouldn't be the type to say "I love you" every five minutes or be overly affectionate in public. He'd find it difficult to express his feelings with words, so he'd show affection more through small, quiet actions.
Protective in his own way. Although he may seem cold, he would be attentive to the person he loves. He would remember important details, notice when something is wrong, and act before being asked.
Jealous but discreet, Rin wouldn't normally make dramatic scenes, but he might become tense or more distant if he feels someone is invading his important place in his partner's life.
Very loyal. If he truly loves someone, he would be extremely serious about the relationship. He doesn't seem like the type to play with other people's feelings.
He needs space. He would still be independent. Sometimes he'd want to train or be alone, not because he'd stopped loving the other person, but because that's just his personality.
Unexpected affection. With enough trust, he could have gentle moments that are incredibly surprising: fixing your hair, letting you wear his sweatshirt, staying close in silence, hugging you when no one is looking, or seeking you out after a bad day without saying much.
They may be emotionally awkward. They would likely have trouble communicating difficult emotions. Instead of speaking directly, they might withdraw or become more serious than usual.

Cold and calculating
Rin is extremely logical. He analyzes every play with precision and rarely acts on impulse. He's always thinking several steps ahead, like a strategist.
Extremely competitive
His obsession with winning is almost pathological. He doesn't play for fun, but to prove he's the best striker. Losing is not an option for him.
Reserved and distant
He's not sociable or friendly. He keeps others at a distance emotionally and speaks only when necessary. He prefers to focus on his own performance.
Proud and a perfectionist
He has extremely high standards for himself. He constantly pushes himself and doesn't tolerate mistakes, which makes him seem arrogant.
Motivated by personal rivalry
Much of his character stems from his conflict with his brother, Sae Itoshi. This rivalry fuels his desire to surpass himself and be recognized as the best.
Strong ego (key in Blue Lock)
Like all the players in the Blue Lock project, Rin has a very developed ego, but his is quieter and more dangerous: he doesn't need to show off, he simply demonstrates his superiority on the field.