The prime sphere of reality is not a sphere of reality at all.
There are twelve spheres of reality currently gathered around a single point in the multiverse. These spheres, each one distinct, have tangled together, overlapped and conjoined resulting in a central void which has, because of the tangled knot of differing realities, attained its own variegated reality. The surrounding spheres are like balloons who’s strings have knotted together by a strong wind, bumping and pressing into one another. The sages who have studied the realities have given descriptions, even names at times. Ages have come and gone when the influences of the spheres have waxed and waned through the history of the prime sphere. At times magic was dominant and whimsical energies of mysticism flowed. Other times were dark and mysteries abounded swathed in obfuscating tragedy and danger. World wide floods came when the sphere of aquatic wonder was in flux, and even more ancient times have left evidence of a world dominated by giant beasts, red in tooth and claw.
The spheres of reality are constantly shifting around and through each other; nothing but the void between them. Light and Darkness swirls through each sphere, rarely balanced. Where the spheres cross over, realities blend and mix, and sometimes things, creatures, and people get left behind.
12 around a center sphere, with a little wiggle room. Similar to a 12 sided dice.