Magic of Thorn's Mystara: Blackflame Lanterns

While the use of magic is tightly regulated by the Special Council of the Ministry of Guilds and Services, there are those who practice their shadow craft for coin, rather than the good of the empire and blessing of the Karrnath. Knowing what their brethren are capable of, the magecaptains of the Imperial Army have developed a number of devices with which to minimize the chaos sewn by rogue bahrthron.

The blackflame lantern is one such item, consisting of an iron lantern frame, the interior paneled in wood or treated fungal timber. Rather than oil, the fuel reservoir holds six to eight ounces of water, into which dangles a long, woolen taper. The four sides of the lantern are left open, but can be fitted with panes of approximately the width and height of a dwarf’s hand. Typically, the sides are fitted with wood or glass panes. When on high alert, one of these panes is swapped out for a specially cut lens of black dragonstone. 

When blackflame shines through a precisely cut and ground lens of black dragonstone, the resulting radiance neutralizes illusory magic, as the true sight spell. Dopplegangers, beings that are invisible (whether by spell or ring), shape-changed, polymorphed, or those in a lycanthropic form are seen for what they truly are.  Elven cloaks’ hide bonuses are likewise neutralized. The radiance does not dispel the magic, thus if the lantern is turned away or if the revealed wizard steps out of the cone of effect, any such illusory magic resumes its function.

Black dragonstone lenses are extremely fragile, and are highly susceptible to the stone-burning effect of blackflame. Lantern bearers must succeed in a Saving Throw vs. Paralysis when removing a blackflame-“heated” dragonstone lens, or the icy tingling may cause them to drop it. Wearing gloves grants a +2 bonus to the saving throw. Exposure to blackflame for more than an hour will cause the lens to shatter, with a 20 percent chance of it exploding, dealing 8d6 cold and electrical damage to all within 30 feet.

Dragonstones of the size needed for crafting blackflame lenses are extremely rare, and finding one completely clear of the deeper purple veining rarer still.