The former capital of the Nagi, Theuban was the site of the Nagi Holocaust (2A 5871 - 2A 5882) at the hands of the false Third Empire under Trollump. The city was destroyed unintentionally when a joint Imperial and Dwarven liberation attempt caused a gigantic explosion when an incendiary bomb ignited a large methane pocket in the swamp. This led to an international incident called the Theuban Affair and the Nagi largely removing themselves from external society.
Nowadays, Theuban is a memorial to the millions who died during the Holocaust, and remains ruined and uninhabited. The swamp around it is sometimes used for mining lead ore, but miners remain respectful and steer well clear of the ruins.