VENGEANCE OF VAMPIRELLA #8 CVR B OLIVER

In order to resurrect the Danse Macabre, Vampirella must first discover what secret Mr. Sabastain was so desperate to keep hidden that he would summon and bind one of the legendary Hounds of Pandemonium to protect it.
Who or what is Abbadon? And could it end the reign of Nyx-or will it bring about the end of all life as we know it?