User blog comment:Commdor/Mass Effect 3: Leviathan trailer released/@comment-4118072-20120824201408/@comment-1221773-20120824203718

My conclusion from available lore and preview information is that Leviathan and the Leviathan of Dis are two entirely different Reapers, and leaked information (which I would like to avoid discussing in detail here for now to spare others from spoilers) backs this up. We'll know for sure on Tuesday, but I don't think I'll be wrong.

Even if Leviathan and the LoD do turn out to be one and the same, then the DLC info would simply be added to the existing LoD page in a separate section.