Realms of the Multiverse
8/25/628
We live in the Third Age.
The First Age ended with a calamity of the God's making. At its end, a few mortals gained control over arcane magic, inflated the Astral Sea, and created the Divine Interdict, making it much more costly for the gods to work directly in the world.
The Second Age ended when the magic of the first arcanists was turned to interplanar war. Many realms, big and small, were laid to waste. Society collapsed.
In the third age no such calamity has arisen . . . yet . . .
The Multiverse is divided. The inner multiverse has dozens of small realms, created by powerful magic which a few mortals may learn to control. Thematically designed, a realm might be a giant vast desert, a peaceful realm of farms from horizon to horizon, locked in perpetual spring or autumn, or any other idea which might spring into the mind of someone powerful enough to wield the right magic.