Complex sentence: The Children of Misfortune is a myth which has existed for hundreds of years: that children born with red eyes will bring terrible misfortune, such as death and destruction, which in this case actually happens.
Split into simpler sentences: The Children of Misfortune is a myth which has been ongoing for hundreds of years. The myth is telling that children born with red eyes will bring terrible misfortune, such as death and destruction, which in this case actually happens.