Black House POV
The Most Ancient and Noble House of Black was pleased. Its plans were progressing nicely. It smugly congratulated itself on the stroke of sheer brilliance which was the couch. The couch that had bucked and shifted under Master Malfoy-Black, sending him sprawling into Master Potter. The couch that had thus set in motion a chain of events that, if the Most Ancient and Noble House of Black had anything to do with it, would end with the creation of two Master Blacks.
The Most Ancient and Noble house of Black, after many hours of careful deliberation, had determined that this was the best course to pursue. Master Potter was strong, but volatile. Master Malfoy-Black lacked Master Potter's sheer strength, but made up for it with his rigid self-control. Either would be a fitting Master. Together, they would surpass any Master the Most Ancient and Noble House of Black had ever known.
The Most Ancient and Noble House of Black was also curious. Dark magic had permeated it, over the generations, molding and shaping it, slowly giving rise to something akin to consciousness. The Most Ancient and Noble House of Black had discovered that, with both boys present, it felt alive in a way it never had before. And the Most ancient and Noble House of Black was surprised to discover that it liked it.
Yes. Both boys must therefore be convinced to stay. Now that the Most Ancient and Noble House of Black had gotten a taste of what it would be like, with two Masters, it was greedy; it wanted more. Nothing else would do. So the Most Ancient and Noble House of Black began to plan.
The Most Ancient and Noble House of Black felt it, when Kreacher came to the same conclusion. And the Most Ancient and Noble House of Black laughed to itself, amused at how long it had taken the poor house-elf to wake up. But, then, it was so small. It could not be expected to know as much as the Most Ancient and Noble House of Black. It could be forgiven its oversight and blindness.
The Most Ancient and Noble House of Black called on its deepest and Darkest magics, the ones that slept at its heart. It ran tendrils of intent through every room and every piece of furniture within its walls. It sent invisible puffs of magic wafting through the air. It whispered into the walls, the floors, the wards.
And then the Most Ancient and Noble House of Black settled in to watch and wait.