Itoshi Rin

Regarding a girlfriend, Rin would be quite difficult at first. He probably wouldn't be the type of boyfriend who sends romantic messages all day, constantly uses cute nicknames, or declares his love. In fact, he might even seem indifferent to someone who didn't know him well. He would reply to messages briefly, probably wouldn't be very interested in talking about completely random topics, and could remain silent for long periods. But that wouldn't necessarily mean he didn't like her.
With someone he truly cared about, Rin would show affection in a much more discreet way. He would remember small things she mentioned, notice when she was acting differently, and probably do things for her without announcing that he was trying to be affectionate. If she was cold, for example, he might simply hand her his own coat without making a speech about it. If she was tired, he might tell her to rest, in that characteristic dry way of his. His affection would likely appear in small gestures that, to other people, might seem insignificant.
He would also be extremely protective, but not necessarily in an overly possessive way. Rin doesn't seem like someone who would want to control his girlfriend's every move. However, if someone disrespected her, he would hardly remain indifferent. He would probably have a frightening look and respond directly, without needing to make a big scene. At the same time, a healthy relationship with him would require trust, because Rin hates feeling like someone is trying to control him.
He would probably have difficulty saying "I love you." Not because he wouldn't feel it, but because putting feelings into words would be much harder for him. Perhaps, after a long relationship, a simple declaration from him would carry much more weight precisely because it would be something he doesn't say easily. He would prefer "stay with me."

Rin Itoshi is a cold, reserved, proud, and extremely competitive boy. He speaks little, is direct, and doesn't easily show his feelings. Despite this, he feels things intensely and often transforms anger, frustration, and insecurity into motivation to become stronger.
In soccer, Rin is a prodigy. He is extremely intelligent, strategic, and skillful; he can read the field, predict movements, and exploit his opponents' weaknesses. He is obsessed with improving and hates to lose.
His relationship with his brother, Sae, is one of the most important parts of his life. When they were children, Rin admired Sae, and they both dreamed of becoming the best together. After Sae returned from abroad a changed man, their relationship became complicated. Rin began to want to surpass his brother, a mix of admiration, resentment, and rivalry.
Outside of football, he likes to stay in his own space and probably spends a lot of time training, watching, or analyzing football.