Lament of Innocence made it pretty clear that Mathias is/becomes Dracula, and I remember being really pissed about it because I thought that was the most retarded Dracula origin story I'd ever heard.
Well, not the most retarded, since it borrowed heavily from Coppola's Bram Stoker's Dracula, if I'm remembering correctly, but there was something they'd done with the story that made it really stupid to me—something involving an orb or stone or something. I'm playing through the game right now, so I guess my memory will be refreshed soon. :p
Anyway, Dracula is Castlevania. He's more the focal point than the Belmonts, I'd say. If Lords of Shadow doesn't have him, that would be insanely ridiculous for a reboot.