Not only that he not "personally" knew the Doctor, but at least knew of him, but also his first incarnation. But that made me realize, how could that be, when not even the Time Lords at that point had caught up with him yet?

I just find it interesting that this character we've never met before mysteriously seems to have knowledge about the Doctor, that maybe he's even been following him for a long time now.

My first thought is that maybe, through all his travels, the Doctor has become sort of ... noticed. But again. Why didn't the Time Lords go after him before then?