The poisoned iron causes non-magical metal weapons to break.
The Iron Crisis is an artificially manufactured shortage of iron occurring in the year 1368 DR in the Sword Coast area of Faerûn. It was masterminded by Sarevok Anchev and his adoptive father Rieltar Anchev, using the local branch of the Iron Throne mercantile consortium in the city of Baldur's Gate as their base of operations.
The Iron Crisis was achieved by a combination of 4 main elements:
- poisoning iron ore and and disrupting the mining activities in the Nashkel Mines
- heightening the activity of bandits along the Sword Coast; achieved through the cooperation of the Blacktalons and Chill bandit groups
- the rise of diplomatic tensions between Baldur's Gate and the nation of Amn; influenced by spreading rumors that Amn was responsible for the crisis and thereby provoking Baldur's Gate to threaten war with Amn
- exploitation of the Cloakwood Mines to develop a reliable source of "untainted" iron ore
The Iron Throne's goal in this was the monopolization of the iron ore trade in Baldur's Gate and surrounding areas through the sabotaging of the Nashkel Mines, the crippling of trade within the Sword Coast and providing iron ore from their secret mine in the Cloakwood, while the looming threat of war with Amn would cause iron ore demand to skyrocket, thereby enriching the Iron Throne and its leaders.
However, Sarevok's goal differed from that of the Iron Throne. He sought the destabilization of Baldur's Gate's political elites in order to get elected as the Grand Duke of Baldur's Gate. He would then use that position to start a war with Amn which would help him ascend to the throne of Bhaal through the massive amounts of death caused by such an endeavor.
While the Sembian headquarters was aware of the plan to create a stranglehold on the iron ore trade along the Sword Coast, they were obviously not aware of Sarevok's plans and as communications with the Baldur's Gate headquarters became more infrequent, they sent an emissary to determine why this branch of the Iron Throne has foundered.
When the time came for Sarevok's coronation ceremony, a party of adventurers lead by another Bhaalspawn, interrupted the proceedings and exposed Sarevok's plans to the city's leaders and nobility who were gathered in the Ducal Palace. After a short battle, Sarevok fled to his inner sanctum with the help of his mentor Winski Perorate. There Sarevok, along with his allies Tazok and Semaj, fought a great battle with the Bhaalspawn and party and were eventually defeated and killed.
This brought and end to the Iron Crisis and the looming specter of war with the nation of Amn.