The Yuuzhan Vong and their Chazrach slaves are one of the few known alien species in the Star Warsuniverse to have originated outside the Star Wars galaxy. They are a race of religious zealots that genetically engineer and grow all of their technology organically and view mechanical technology as blasphemy. The Yuuzhan Vong endeavor to improve their physical capabilities through organ grafting. Notably, only one Yuuzhan Vong is able to touch the Force or seemingly be felt through it, something the Jedi find very mysterious, since all living things are supposed to have, in some way or another, a unique Force energy signature distinct from other species. Later, it is discovered they were stripped from the Force upon separation from their symbiosis with the sentient planet Yuuzhan'tar.
The Yuuzhan Vong invasion (also: Yuuzhan Vong War) occurs in the Star Wars universe timeline between twenty-five and thirty years after A New Hope and the Battle of Yavin. It appeared and was chronicled in The New Jedi Order series of books. The series also saw the introduction of many new characters, such as Ben Skywalker, son of Luke Skywalker and Mara Jade.
The conflict involves the invasion of the main Star Wars galaxy by the extragalactic alien race of Yuuzhan Vong. The invasion began approximately 25 galactic standard years after the Battle of Yavin, although there is evidence that the initial stages of the invasion had been underway for almost 4,000 years. The war ended five years later, the retreat of the defeated Yuuzhan Vong largely due to the ongoing efforts of the Galactic Alliance. The invasion has been chronicled as one of the most costly wars in the galaxy, due to the death toll it produced. It also saw the deaths of many of the major characters, including, but not limited to, Chewbacca, Anakin Solo, and Admiral Ackbar, as well as 365 trillion sentient beings.