Forgive the canon connections here but...
LoS is set in 1047 which is way before LoI, where we learn that Matthias becomes Dracula later on. So maybe if Drac is in LoS, he pulls a "Terminator" move & time travels back to the VERY beginning to wipe out the Belmonts before another generation can appear? (That would lend some credence to the "destryong the Belmonts" line in the 1st trailer). Yea that would not be very original whatsoever but who knows. But then again, maybe time travel is involved somehow...cuz how else will they explain how Carmilla, Laura and Cornell are in the game when they are in games 7-800 years later? You gonna tell me they are all older than Dracula and have been around the whole time? I don't buy that.