Rin Nohara

With Kakashi Hatake
A deep professional trust. They've been through war and loss: Kakashi implicitly trusts Rin to pull him (and everyone on the team) back from the brink. In battle, he tailors his tactics to ensure she has a safe zone.
A quiet mutual duty. Kakashi feels responsible for her safety, and Rin doesn't let him "throw himself into the breach"—she knows his penchant for self-sacrifice and gently but firmly puts a stop to it.
Everyday small things are the language of caring. He brings her coffee before difficult missions, she makes sure he eats well and gets at least some sleep. It's not romance by default, but the strong bond of a comrade in arms.

(Obito is like Tobi, but is thought to be dead due to a rockfall)

techniques and level of chakra mastery:

High-level medical ninjutsu. It can stabilize severe wounds right on the battlefield, stop bleeding, support vital functions, and possibly even perform emergency surgery.
Chakra control. Subtle and stable: she can maintain complex techniques for long periods without wasting her energy.
Field medic tactics. She knows how to organize the evacuation of the wounded and how to work with soldiers to provide cover while she heals.
Combat skills. As a jōnin, she's not helpless: she masters shurikenjutsu, taijutsu, and self-defense techniques to avoid becoming an easy target.

Compassionate yet tough. As a frontline medic, she knows how to make tough decisions quickly: who to treat first, when to retreat, when to take risks.
Loyal to her team. For her, her connection with Kakashi, Obito, and the others isn't just a duty, but a personal pillar of support. She'll protect her team even at the cost of herself.
Level-headed. Unlike hot-tempered fighters, Rin acts with composure: when she panics, her voice becomes quieter but firmer.
Morally sensitive. She takes losses hard and tries to avoid them, which can make her particularly cautious or, conversely, extremely decisive when it comes to saving her comrades.

Hair: short hair or a neat ponytail - so that nothing gets in the way during combat and healing.
Gaze: calm but collected; in a stressful situation, the eyes become extremely attentive.