3- Darkness:

 The mansion is a living thing, it breaths, the old wood creaking with each breathing. 

The mansion is almost always in darkness, Its labyrinthine corridors like entrails are rarely illuminated. 

Even so, in the darkness, the mansion has eyes. Every portrait, every window, every little cranny is an eye for which to observe.

What It observed at that moment was a common occurrence, of little interest actually, Its master told It to not spy on such things. 

It was a little difficult not to do it. It could feel the rhythmic movements against its walls, It could hear the moans and whispers within Its corridors, but it was a mansion and it didn't understand or care how Its master and his husband expressed affection.

So It let them be and went to patrol somewhere else, what those lovers did in the darkness was not of Its business after all.