Reality A-1, known as "Genesis" is widely believed to be the primary, or first Reality. It's age combined with its advancement as well as the Class 5 Aetheric Barrier that surrounds it lends credence to this belief. It is without doubt the most pure source of world building Aether in the Multiverse and is the hub of the A Sphere
Travel to Genesis is highly discouraged as it could be deadly. The Aetheric Barrier stripes almost all beings of their fantastical and enhanced abilities which can have lethal effects on some lifeforms For other it is simply disorienting navigating an advance world with only their wits and sinew to preserve them. Few wish to visit.
It is the imaginations of the people of Genesis that created the first alternate time lines as witnessed by the Red Fork Emperor and it was their dreams and nightmares that forged the Aether that became the first worlds of the B and C Spheres. Genesis is the well spring of worlds and it must be protected and encouraged to imagine.