Theory on Rin. Please read, it's really quite logical and a little heartbreaking.

[Piratefish]

The two Mist Nin were disappointed that Kakashi killed Rin. We know next to nothing about her. Why were Rin and Kakashi so far afield from Konoha, without any obvious purpose?

Rin could have been an enemy agent. She was highly placed in Konoha (student of the Hokage) and could easily gain access to any number of secrets.

So here's the theory. Rin was a double-agent, either through forced means (kidnapping of family or the like) or through free will. She escapes Konoha with a secret (maybe even the extended information on the Hiraishin, personally written by Minato) and Kakashi realizes it. Maybe she's been acting off lately, maybe she's been asking weird questions. Maybe he just doesn't want to leave her side after Obito's death. He tracks her, catches her and forces her to reveal the reason why she left. Heartbroken, he is forced to kill her to protect Minato/the village as a whole. With her last breath, she conveys her regret over forcing him to do this, just as the Mist is about to reach them. Kakashi's Mangekyou unlocks from him killing his most precious person in the world.

[Hipster Deidara]

I think many of us assumed she was an agent. If i recall, someone made a thread about this before :/

[cptenn94]

the only issue is konoha reinforcements were not far behind.... other than that who knows

[Piratefish]

the only issue is konoha reinforcements were not far behind.... other than that who knows

Kakashi could have raced ahead, or taken off immediately after informing them (mostly the same thing).

[Arcane Angel]

A lot of people have said this and may well be possible. For Kishi not to have revealed anything about Rin goes to show that she has some secret hidden indeed.

[★LssJBroly]

That would give Obito a reason to hate the village because Kakashi chose the village over Rin, in order to protect the Village's secrets.

[nNoma]

Good theory, it's sad, but fitting if you ask me. Kakashi's life has always been full of loss and regret, but he tries to be the best possible sensei to his students. I think through this suffering he has learned a great deal about life, and even when you think back to what he said to Sasuke just before he went with the sound four, it really relates to how he had lived his life.

[mikeeozua]

Im thinking that Kakashi must have killed Rin for a good reason. Otherwise why would Minato (Or hiruzen if he was still hokage at the time) put him in the ANBU?

[rollin]

i think it has to do with zetsu mentioning guinea pigs or in the mangastream translation experimental bodies

[WOOD STYLE l MADARA]

The two Mist Nin were disappointed that Kakashi killed Rin. We know next to nothing about her. Why were Rin and Kakashi so far afield from Konoha, without any obvious purpose?

Rin could have been an enemy agent. She was highly placed in Konoha (student of the Hokage) and could easily gain access to any number of secrets.

So here's the theory. Rin was a double-agent, either through forced means (kidnapping of family or the like) or through free will. She escapes Konoha with a secret (maybe even the extended information on the Hiraishin, personally written by Minato) and Kakashi realizes it. Maybe she's been acting off lately, maybe she's been asking weird questions. Maybe he just doesn't want to leave her side after Obito's death. He tracks her, catches her and forces her to reveal the reason why she left. Heartbroken, he is forced to kill her to protect Minato/the village as a whole. With her last breath, she conveys her regret over forcing him to do this, just as the Mist is about to reach them. Kakashi's Mangekyou unlocks from him killing his most precious person in the world.

maybe threads like this are alrady made..
although, i readin this fr the 1st tyme..
theory seems legit!

[Big bengi]

You might be right but i beg to differ, i think he called her because she was a weak member of the team thus she was a liability. We have seen ninjas kill fellow ninjas for simple reasons like this for example kisame.

[Lilvic92]

You might be right but i beg to differ, i think he called her because she was a weak member of the team thus she was a liability. We have seen ninjas kill fellow ninjas for simple reasons like this for example kisame.

That would just make him a hypocrite for stopping Sasuke from killing Sakura...
Plus that is completely out of Kakashi's character.

[Piratefish]

Yeah, I figured something like this might have been posted before but thought I'd see what people thought of my version.

You might be right but i beg to differ, i think he called her because she was a weak member of the team thus she was a liability. We have seen ninjas kill fellow ninjas for simple reasons like this for example kisame.

This is WILDLY out of character for Kakashi (he's not remotely similar to Kisame) and unlocking the Mangekyou means extreme emotional torment.

[★The Shogun]

This is a possible theory.

[~Shadowhunter Princess~]

Seems legit. I never thought about it like that