Francisco d'Anconia: Who is He?

In chapters five and six, I have developed a strange interest in Francisco d’Anconia's character. The mystery he represents is intriguing and the further I read, the deeper it gets. Why would he purposefully destroy his own fortune and future? His character is complex and slightly weird to say the least. It's difficult to figure out why he's destroying his own work, as well as Dagny's. I know they have a past, but I can't even begin to fathom what is driving him to ruin her railroad, especially when he knows just how hard of a worker she is and how proud she is of that work. When Francisco has a conversation with Rearden, another strange interaction, it further deepens the mystery of his character. Why would he point out the reality of Rearden's life to his face? He does it in such a suave and respectful manner that makes it seem like a normal thing to say, but it isn't at all. Although I think it was necessary for someone to make Rearden understand that he needs to make changes in his personal life, I don't think that person should have been Francisco; he has no right. Hopefully, though, Francisco's words will speak to Rearden and he'll make the appropriate justifications in his life, because enough is enough. Another weird thing that I didn't understand was why did Francisco insist that the stories about the existence of Atlantis were true? Given the ambiguity, complexity, and sort of dignity of Francisco's nature, it makes me wonder if he's the "John Galt" everybody speaks of.