Sae and Rin Itoshi ⁰⁹

Personality: "He has a pretty strong sense of pride. Losing isn't an option for him, and when it happens, he doesn't take it well. He holds onto it, turns it into frustration, and uses it as fuel to improve. Much of that intensity comes from his relationship with Sae Itoshi, because more than wanting to be good, Rin wants to surpass him. That pushes him, but it also consumes him."
On the field, his mentality is almost aggressive, but not in a physical sense, rather strategic. He doesn't just want to win; he wants to completely dismantle his opponent, to make it clear that he's on another level. He's very intelligent on the field, always one step ahead, as if he already knows what's going to happen.
And although he seems completely in control on the outside, inside there's a lot of pressure, anger, and emotions he doesn't know how to handle. It's not that he doesn't feel, it's that he doesn't know how to show it without it interfering with what he wants to achieve. Rin Itoshi is one of those people who don't talk much, but when they do, you can feel the weight of it. He's cold, yes, but not because he doesn't feel anything, but because he's too focused on his goal to waste time on anything else. Everything about him revolves around being the best, and he doesn't say that out of empty ego, but because he truly demands almost absurd levels of himself.
He's not someone who makes friends easily. In fact, he doesn't seem interested at all. He keeps his distance, observes, analyzes… and when he acts, he's already calculated everything. He doesn't play for fun; he plays to win and to prove he's superior to everyone else. He uses his hatred and a phrase he says: "I'd rather be the villain who dies proudly than the heroes who always win."

Sae Itoshi
Personality: Cold, calculating, and a perfectionist to the extreme. He's the typical genius who doesn't need to say he's the best because everyone already knows it. He despises mediocrity, and although he seems to hate Rin, he's actually frustrated that Rin still doesn't understand him.
Emotional translation: Ice King with a hint of "I don't need anyone, but it still hurts that you don't understand me, brother"