Complex sentence: The three remaining friends decide to avenge John's death and they set to hunt the beast but their task won't be easy since there's a legend saying that the beast is an incarnation of an ancient hoodoo spirit in the form of a killer shark.
Split into simpler sentences: The three remaining friends decide to avenge John's death and they set to hunt the beast. But their task won't be easy since there's a legend saying that the beast is an incarnation of an ancient hoodoo ritual in the form of a killer shark.