User blog comment:BannedLagiacrus/Monster Hunter Ecological and Lore Info Blog/@comment-6050823-20160207060415/@comment-6050823-20160208015233

I almost forgot about this bit info from MHX about Fatalis (Note: Fatalis isn't in MHX but is sort of mentioned). The Black Pieces from that Great Sword actually can be found in just about every area oddly. So in sense, Fatalis potentially appears everywhere.