As members of the oldest beings in the universe, the Watchers saw all.
It is the oldest existing.
Sasha may not have pulled the trigger on Andre, but someone he knew where to find their oldest brother, who had been protecting Katie when he was rendered dead-dead.
The oldest Egyptian or Hindoo philosopher raised a corner of the veil from the statue of the divinity; and still the trembling robe remains raised, and I gaze upon as fresh a glory as he did, since it was I in him that was then so bold, and it is he in me that now reviews the vision.
It's the oldest bond there is, old enough to keep the mating bond from shifting when she wins her deal.