what she knew for a fact , since every older person shed ever met seemed to be in agreement about it , was that they were on an island that once boasted one of the worlds greatest kingdoms , which had perished in a single sweep of the sky-high waves , sparing only those who lived up in the mountains : the shepherds and villagers who , in the bitter aftermath , once plants had been killed by the ashes and the sunlessness , and their flocks had to be butchered and eaten before they died off too , degenerated into monsters .