The creators of bitcoin still control something like 25% of all bitcoins, which gives them a huge amount of leverage in manipulating the bitcoin economy. So it's interesting that nobody knows who they are.
Where did you get that, out of that PDF? The number 25% sounds extremely high.
I have read this PDF before, a while ago, and I don't remember that stat. A quick glance tells me that they say that 2 addresses have over 500,000 Bitcoins, but that's just 4.6% (or more, obviously) of the total 10.7M issued so far. And there's no proof that this is the creator of Bitcoin. In fact, it's more likely one of the large exchanges!
So, please help me understand your statement. If it's buried in the text of that PDF, my apologies.
http://eprint.iacr.org/2012/584.pdf