Storms in 406 ended up dumping a significant amount of the waste which the IU had deposited on Pleoh into the ocean, and the effects of these pollutants rapidly spread to the waters near Nezuma.
As a consequence, Nezuma severed ties with the IU. Skobra had been asked by the IU to provide fish to Lornith, but seeing what had happened to Nezuma, they refused. The IU threatened to make use of their waters for fishing regardless, and a war broke out in 411, with Nezuma and Skobra fighting the IU.
Nezuma and Skobra were overpowered and surrendered in 417. The IU did not incorporate Nezuma and Skobra as full members, a state of affairs which continued to cause strife. While this was happening, a number of people from Nezuma and Skobra fled to Adari and Griesh rather than live under the control of the IU.