Quote Originally Posted by ASSpirine
Nope, never heard of it. We could start speculating...
Well, my thought. Was it Itachi's best friend? Whom he had killed?
We know that the Kyuubi knows him, Itachi would have been far far too young to be involved in that fight. More likely someone Kakashi's age+ We didn't ever get the name of the person that Kakashi got his eye from right? Maybe him, or maybe I'm way off base and it is someone even older, I also forget if we got the name of the first person to achieve Mangekyu Sharingan but if not he is a possibility.

It seems he would try and make this "important" name one of those two, to me anyways.