The End Of The World As We Know It
A mythallar is usually a large, polished crystal as tall as a man, though it may take other forms as well. The crystal sheds a very bright light—almost as blinding as looking directly into the disc of the sun—with dimmer shadows and shapes moving across its surface. An ornate stand keeps the crystalline device in place. Like a mythal, a mythallar creates a city-sized envelope of pure magical energy. Unlike a mythal, however, a mythallar always incorporates a major special ability that permits the creation and use of quasi-magic items.
Quasi-magic items function exactly like normal magic items within the bounds of a mythallar but become inert when taken beyond its borders. The arcanists who first discovered and used mythallars viewed this restriction as a fair tradeoff, since the creation cost of any quasi-magic item, no matter how powerful, decreased by 90 per cent. This reduced cost opened up item creation to even low-level spellcasters and made the creation of vastly powerful, near-artifact items feasible. Without mythallars, Arcadia would never have reached the zenith of magical power that it achieved.
Touching a mythallar is a lethal decision. Anyone who touches the device is instantly slain (no saving throw). Any item (even true magical items) that touches it, (except the stand) is instantly disintegrated. Any undead that touches the mythallar are destroyed.