The Plague Bridge

There are many open hostilities between the Lords of the Isles. Many, many more of these are well hidden. No hatred was ever more apparent than the feud between the Lord of the Iron Helm and the Prince of Serpents.
It all began when the realm of the Iron Lord suffered greatly from a foreign disease. Plants, animals, and people suffered equally, aggressively decomposing rapidly. With flesh and bone dropping, and knowing that time was short, an urgent message was sent for aid. Envoys traveled in threes, coming to each Island, and begging for supplies and medicine. Although they were turned away from all they went to, it was the Serpent Prince who stood out among the others. Already known for his cruelty, he humiliated the envoys before his gathered people. Only one of the three envoys was sent back, after being told that unless the Lord of Iron was to walk into his keep, there would be no aid. The enraged Iron Lord accepted the insult as a challenge.
Immediately construction on a grand wooden bridge began, long enough to cross over the waters between their land. Swiftly nearly the entirety of his people were conscripted to this project. With nothing left to lose, the island suffered from severe deforestation. Assailed by foreign ships after the news had spread, those working suffered under constant arrows. However, the sickness had taken away almost all feeling from them, and many simply pulled out the arrows that stuck to them.
Two months later, the bridge had been fully constructed. The sickness was spreading over the wood used as fungi grew along the planks, and the waters became thick where they touched. Bodies that could no longer sustain life fell into the waters below, further corrupting the area. When the Lord of Iron stepped onto the island with his hundred warriors, the land had become much like his own had in the early days of the sickness.