Complex sentence: Chelsea explains that when her people came to America, the creature hid in them, it is a vampire and picked off each member of the town until only the three girls and their father, the Reverend were left.
Split into simpler sentences: Chelsea explains that when her people came to America, the creature hid among them. It is a vampire and picked off each member of the town until only the three girls and their father, the Reverend, were left.