This spell is a part of the Dishevel spell chain and can be found in the Dishevel rune stone.
Unlike tornadoes in nature, the dark symbol of air - the Tornado - isn't purely destructive. It is chaotic. Chaos itself isn't inherently destructive. This was shown to the aeromancer time and time again, with the latest lesson being found in Weapon Rush. The Tornado does not need to harm. It simply disrupts. Air Dome is yet another example of that disruption.
Called up around a target - the aeromancer or whoever they choose to shelter - the Tornado's fury doesn't scatter outward this time. It curls into a churning sphere instead, thick and violent along its edge, calm at its center. Nothing loosed from outside can punch through that shell to reach whatever's sheltered within it, and nothing thrown or fired from inside can escape it either - arrows, bolts, thrown weapons, none of it crosses the boundary in either direction while the dome holds. The wall isn't gentle to bodies, either: anyone stepping through the boundary, entering or leaving, must pass a Hard Brace check or be knocked flat by the wind fighting to keep its shape.
It's a strange kind of shelter - as much a cage as a shield, depending on which side of the wall you happen to be standing on when it goes up.
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