The Ether Tides are a constant ebb and flow of magical energy that pervades all of Akrlynor outside a few locations, notably the Shadowsfall Lake, the Mouth of the World, and the Dead Steppes. This energy is created by power flowing out of the interior elemental planes (the pure "Magic" ether is believed to emanate from the Fey Plane through Fyrelight Glade, and Spirit Ether seems to flow from multiple sources) which pools and moves within The Curtain, the barrier which contains Akrylonor from whatever other universes lay beyond. The only other form of ether known to exist was that produced by the Dark Source, which relatively few could locate, fewer could wield, and none without consequence. Some few researchers have speculated that a "Void" or "Star" ether exists beyond The Curtain, and may be the source of the power that many of the New Gods draw on (or the Dark Source, before it corrupted the power into Dark Ether)
The Ether Tides are drawn upon prominently in the various forms of magic. Arcane workings bind or channel ether into forms that suit a mage's desired effect. Druidic magic exerts an approach closer to guiding than binding, more difficult to work completely against natural flow, but less likely to end with any unintended consequences if a binding fails or goes awry. Divine magic is produced when worshippers' own ethereal essence draws in other flows (though still primarily those of Spirit) and channels it to a worshipped entity. Entities that become aware of this effect are able to wield the additional ether, or direct it back to their worshippers in controlled manners.
Numerous creatures have a natural aptitude or affinity for various ethers, the most prominent being Dragons, who take in ether as eggs and as they mature. This heavily influences the aspects, powers, and sometimes form of the dragon.