The Forge of Woe

Kashar the master smith lifted himself painfully from his bed. As with the last two days, he was greeted by a powerful wave of nausea. Unable to stop it, a gorge of bile rose. Today was different. The last few days it was simple bile, but today black blood came up.

It is well that there is no more Mithral thought Kashar, for surely my strength could not handle a seventh blade...

Before entering the forge, Kashar was attended to by the ancient Dwarven priests. They chanted their prayers that would grant him some strength to complete the task ahead, and to shield him from the heat of the forge. Their spells could not, however, protect him from the invisible scourge which brought sickness and death to all who would use the Forge.

The Mithral blades being built were an act of desperation. The human King Eathen the Terrible's forces were hard-pressing the dwarves to seize the mineral rich mountains. To help bolster their defence, the Dwarven Thane released the reserve supplies of Mithral to be made into a set of enchanted swords. And today Kashar was making the last of them.

Even as he worked the blades, his life force ebbing away, the blades absorbed some of the dying smith's life energy, and so the Six Blades were gifted by his courage and his skill.

Finally, Kashar finished forging the last blade. The sword was not finished, but that work which remained did not require the use of the forge. Painfully, he walked away from the forge, the feeling of rising heat reminding him that the protective spells would soon expire.

Placing the sword on a stone shelf, well away from the intense heat of the forge, Kashar then turned back to the forge. He looked down into the shaft, which was filled with the light of glowing plasma, hesitated for a moment, and then threw himself down. As he fell, the spells protecting him failed - for a moment he glowed incandescent as the great heat vaporized him, and then he was gone.

The Forge

The Forge is a blast furnace fed by the heat generated by a natural nuclear fission reactor. A plume of superheated air hot enough to melt Mithral raises from the depths. In addition, hard radiation abounds and will irradiate any who use the forge. Dwarves are one of the few peoples tough enough to be able to use the forge (and only with magical protection from the heat) for reasonable periods before suffering radiation sickness. Even the dwarves are not untouched by the radiation, and only those of advanced years and skills will avail themselves of the Forge's power.
Those who use it invariably become sterile and generally do not have long lives afterward.

Normal metals are not safe to use in the forge, for the hard radiation will irradiate the metal and make it radioactive itself. The tools used in the forge are generally only used for a day before being disposed of.
The anvil used in the forge is a magically reinforced stone anvil which still needs to be periodically replaced or resurfaced.

Magical metals are assumed not to become irradiated like normal metals, or if so, to a much lower degree. The Forge's high heat levels allow for magical metals such as Mithral and Adamantite to be melted and forged, though magical protection must be used by the smith to allow use of the forge.

It is possible to create irradiated weapons, such as arrowheads, but the Dwarves have not done so, both out of morality and safety concerns.

Radiation Poisoning

Obviously this is a controversial topic to introduce to a Fantasy campaign, but radiation is as natural a phenomena as heat and light, so with moderation I think it is fair to include it. If this simply does not fit with your own world, then substitute a magical curse on the Forge with similar effects.

Radiation poisoning is accumulative in nature - once a character has been exposed to radiation, their resistance to future irradiation is reduced. Curative magic could possibly heal radiation damage, but it should require rather high level magic to do so.

Now, the exact effects of radiation exposure will vary from game system to game system, but in general it can be considered to have similar effects to disease at lower levels of exposure, and as a poison at higher levels.

The Forge of Woe is radioactive enough to subject users to 100 Rem/ 8 Hour period.

Rem Level Effect on Humans

100 - Minor sickness - Minor Penalties on all actions
200 - Light Radiation Poisoning - Nausea , increased penalties, 10% chance of death after 1 month (infection)
300 - Moderate - Greater penalties,Hair loss, 35% chance of death after 1 month (infection)
400 - Severe - Bleeding occurs, 50% chance of death after 1 month (infection)
600 - Acute - 60-90% chance of death after 1 month (Internal bleeding & infection)
1000 - Acute - 100% chance of death in two weeks.
5000 - Acute - 100% chance of death in 1 week.
8000 - Acute - immediate coma. 100% death in hours.
8000+ Immediate death.

Dwarvish Radiation resistance

Dwarves can be assumed to be more resistant to radiation for a couple of reasons:

1. In most game systems/worlds, Dwarves are more hardy then humans, having greater Constitutions (or related stats).
2. Dwarves are generally a subterranean race, and levels of radiation underground from natural sources are higher then generally found on the surface.

I would suggest that Dwarves have twice the human tolerance for radiation, allowing the Forge to be used up to 2 days without incurring real radiation sickness.

Another take on this can be found here

Plot Hooks

For King and Country

King Varamon's wizard, Salidahn, has divined the approximate location of the Forge of Woe and seeks it in order to gain the ability to forge Mithral and Adamantite (perhaps to produce more Dwarvish Lighting Bottles).

Since the Dwarvish kingdom fell some time ago, the forge and its surrounds have been uninhabited by dwarves (or humans - those which had conquered the territory could not reproduce the mining efficiency of the dwarves, nor could they master the spells necessary to survive use of the forge, even for moments). As a result, creatures of the underworld moved into the area, and unaware of the dangers of the forge, they were subjected to the effects of the radiation. Normal living things, such as humans and dwarves, generally sicken and die. Magical beasts and those long-enured to the depths of the earth react differently, and so now odd mutated creatures abound around the old forge. Those looking for ideas could look at Gamma World or similar game systems for creatures which could be found around the Forge of Woe).

Shadows of the One-Ring

The tremendous fires of the Forge can be the final resting place of powerful cursed magic items. PCs would need to research the location, and as well the advanced heat-resistance spells necessary to come close to the pit. They may also research spells/protections to allow them to resist the radioactive aspects as well. Lead Golem anyone? :)

Breachpoint

After petitioning the Dwarves for many years, the Arch-mage Tazaris finally convinced the dwarves to allow him to make use of the forge in creating a mighty talisman. To this end he created magically enchanted gifts to all of the Dwarvish Cheiftans in order to buy their votes at the Dwarvish Council of the clans. Mightily weapons, ensorceled helmets and other items graced the Chieftans.

Tazaris had intended to use the power of the talisman, once created, to overthrow the Dwarves and claim the Forge for his own. However, some interaction between the talisman he was creating, and the latent powers of the forge served to sunder the fabric of reality in the vicinity of the forge. The resulting energies consumed Tazaris and the dwarves present and metamorphisized them into strangely twisted forms. All contact between the Dwarvish people and the outside lands was sundered.

Now, if the PC's investigate the kingdom, they will find it populated by different factions - remnants of the dwarvish clans, as well as Tazaris and a group of morphed dwarves aligned with him. The forms are simular in nature to Undead, but instead of Death (or negative energy) being the motivational force, all of these beings are animated by a strange combination of Radiation/Pure elemental magic. Their outlook towards the living is primarily of pity and they seek to bring any outsiders closer to the forge and the odd energies, hoping that they will join their number.

The morphed creatures lose energy if they are brought far from the forge and so control of the forge is the primary driving factor of all of the factions.

PCs could be dispatched after magical monitoring by Wizards has determined a strange disturbance, or the energy has spread to the surface and began to morph beings there.

These things actually exist(ed)! (Well, not for use as a forge, and not as powerful as this one has been portrayed...) http://en.wikipedia.org/wiki/Natural_nuclear_fission_reactor
As well, I used the entry for radiation poisoning from Wikipedia.

Now, I'll admit that I'm taking a bit of license with it, but once I thought about it, I had to make this submission.