Complex sentence: The Yuuzhan Vong are a fictional race of sentient beings from the "Star Wars" Expanded Universe that rise as a threat to the New Republic in the "New Jedi Order" series of novels.
Split into simpler sentences: The Yuuzhan Vong are a group of fictional characters from the "Star Wars" Expanded Universe. They rise as a threat to the New Republic in the "New Jedi Order" series of novels.