Ok so I know a lot of people think that it was all Zetsu at Rin's death. This is why I hope it was actually Kakashi that killed rin.
1. Since Minato was absent, it would explain why Obito wanted to kill Minato since he wasn't there to protect Rin.
2. If it was the mist that tricked Kakashi into killing Rin, then it would explain why Obito created the "Bloody Mist."
3. If it really was the Mist ninja that tricked Kakashi into killing Rin through some mist genjutsu, then it would explain why Kakashi, "Let Rin die."
4. It would also show that Obito's eyes ARE connected, and would explain how he has a lot of valuable information. (But he would only be able to see, since it an eye, not hear and everything else.)
5. It would start to explain Obito's path to madness. With his sense of reality inflicted, one of his good friends/ teammate, killing his crush/teammate when all he wanted to do was be with them. I know I would go through some VERY rough times if i witnessed that.
Now, don't get me wrong, it may very well be Madara's doing, but I hope it's not I think it would be more emotional and be a little better story wise, but that's just me. Please do not tell me the things about why this would not make any sense because I am very well aware of all these factors, but Kishimoto still has a lot of explaining to do so just be patient. Thanks for reading a have a great one! Bye