[It's a bit like modern drug dealers fighting over territory. This analogy might be a bit inappropriate, but in terms of cruelty, there's not much difference.]
[As mutual hatred accumulated, some island residents found a permanent solution, which they called the devil's offspring. They used hostages from opposing islands to cast a persistent, unbreakable, malevolent curse.]
[Documents didn't record how the method was acquired, but the author had some speculations. Since the curse was called devil's offspring, it was guessed that the devil appeared in leaders' or elders' dreams on the islands. Another theory was that island residents were possessed by demons from the seabed, thus learning the method. There was also speculation about the presence of a cursed stone slab left by ancestors on the island, which imparted the knowledge of the curse to anyone who touched it.]