Board Thread:Naruto Discussions/@comment-16064415-20140829133523/@comment-1018594-20140831022603

It's been mentioned that Orochimaru knew both his parents, and that they also died when he was young. That's what started his fixation on immortality: he's saddened and depressed by the idea of death and what it does to people.

But knowing Orochimaru, he definitely would have known if his father was the Mizukage, and it might have given him some reason to work out of Kiri if he was.

I think it's just a coincidence in design. The same way everyone thought Pain could have been Obito or Minato when he was just a silhouette.