Sooo, since we basically know nothing about Rin other than she was on Team Minato, and she died sometime after Kakashi Gaiden, I've got a ton of headcanon for her, although it's likely to never affect any gameplay or conflict with anyone because I'll probably always take her from her last canonpoint (right after Kakashi Gaiden). If there's anything you want to dispute me on, or clarify, or just basically comment on my ridiculous theories, feel free to do so!
Updated sporadically. Check every so often if you're so inclined.
First off, Rin is not part of the Inuzuka clan or any named clan already shown in the Naruto series. For the sake of my laziness (as well as not wanting to contradict canon if it should come up), I'm keeping her last name ambiguous.
Her father was a civilian, and her mother was a ninja who died before Rin entered the Academy.
After Kakashi Gaiden, she lived through the Nine-Tails attack and started working at the hospital full time for a while.
When she was seventeen, she joined ANBU (because any named character worth anything needs to be part of ANBU apparently) as a field medic, and life was good! Sort of, as good as it gets, anyway.
She died at eighteen while on an ANBU mission, although I haven't exactly decided on a cause, whether it was by overexerting herself by healing someone or getting killed by an enemy or some other thing.
That's about it, in a nutshell. Again, this is likely to never affect gameplay, just the imaginative (or not so imaginative) thoughts of a mun.
Other random facts:
- She knows that she's technically the weakest member of her team. It's not that she's okay with it, but it's kind of a "what can you do" kind of of situation. She tries her hardest, but with Kakashi the prodigy, Obito Uchiha (still an Uchiha, even if he's clumsy), and Minato the Yellow Flash, Rin's basically the one normal member. A very good medic though (an eye transplant with no lasting damage and only minimal medical tools in a definitely-not sanitary area?). Maybe she won't ever get to be the genius that Sakura would be in the future, but she's good in the way that normal people are good at something.
She's glad to be able to be on their team though, in any case. Wouldn't trade it for the world, and it's not because she's with such a bunch of famous-ish people.
- In the same way, Rin knows that she's the... Well, "least needed" isn't the right phrase for it, since she's their resident medic and definitely pretty important. But Kakashi's kind of screwed up, Obito's always fighting with him and probably has his own issues, so Rin's always the one breaking them up. In that sense, Rin feels that she's supposed to be the one with "good behavior" on the team, to make it less crazy for Minato.
She doesn't mind.
- Despite being a civilian, her father encouraged her to go into the Academy, not that she didn't already want to go before. Secretly, Rin thinks it's because he wants her to be exactly like her mother as a pseudo-replacement, even if he didn't realize it himself. She doesn't resent that though, but that's why she chose to be a medic instead of being a total field ninja, just to separate herself from her mother.
- She knew that her crush on Kakashi was pretty much a lost cause, seeing how detached he kept from absolutely everyone. She was perfectly content to simply be teammates in that way because to her, it was fine if that was as close as she could ever get to him. She sometimes wonders if her crush was a crush at all, and not just pity. That's not to say she didn't try to let him know subtly though, such as sewing that charm into the med pack.
- Rin suspected Obito might've liked her, but wasn't totally sure until Kakashi flat-out told her so after Obito's death. Before that, she'd tried to discourage any hope that Obito might have had, because Obito was never a second best for her, and was never going to be. He was simply Obito, and there was no comparison at all. She loved him, certainly, but it was never in a romantic sense. After his death, she tries not to think about him too much though.
- Had a mild hero-worship crush on Minato when Team Minato was first formed. Got over it quickly. She was a total Minato/Kushina shipper, and liked to tease Minato about Kushina sometimes. Still thinks her teacher is one of the coolest things since sliced bread.
Wow, this got long.