A Clone trooper receives orders to execute Order 66.
Order 66 is a fictional military protocol featured in the Star Wars multimedia franchise. It was first invoked in the 2005 feature film Star Wars Episode III: Revenge of the Sith.
Order 66 was a prime directive programmed into biological control implants that were implemented in all clone soldiers and officers of the Grand Army of the Republic during the Clone Wars. The order was a command for officers to exterminate any and all members of the Jedi Order, allegedly invoked should the members of the order prove themselves traitors to the Republic. Darth Sidious had the cloners of Kamino include this directive into the control chips, and all clones bearing the chips were obliged to comply.
When the Jedi Council on Coruscant learned that Supreme Chancellor Palpatine was the elusive Sith Lord they had been seeking, Darth Sidious publicly announced that the Jedi were traitors. He sent holographic messages to his clone commanders, instructing them to execute Order 66. With no free will to disobey this directive, the clones were forced to comply, and turned their weapons against their Jedi comrades.
Ground troops turned their weapons against Ki-Adi-Mundi on Mygeeto. Ki attempted to deflect the oncoming bolts, but there were two many and the clone laser fire overwhelmed him. On Felucia, General Aayla Secura's own troops turned against her, literally shooting her in the back, and continuing to fire even after she was dead on the ground. Clone fighter pilots shot down Stass Allie on her speeder bike on Saleucami while others brought down Plo Koon's Jedi starfighter on Cato Neimoidia. On Utapau, Commander Cody was ordered to execute Obi-Wan Kenobi. Obi-Wan managed to escape on the back of a varactyl, but the animal was shot down, plunging them both into a body of water. At the time, the clones believed Kenobi had died in the fall.
The most egregious implementation of Order 66 at the close of the Clone Wars came at the hands of former Jedi Anakin Skywalker. Having turned to the Dark Side of The Force, he was now known as Darth Vader and was sent to the Jedi Temple to kill any remaining Jedi. Appearing in the council chambers, Skywalker found several scared younglings hiding. Igniting his lightsaber, her mercilessly slaughtered them.
Following the end of the Clone Wars, Order 66 was further realized in an initiative that came to be known as the Jedi Purge. Darth Sidious formed the Order of the Inquisitors, which was led by Darth Vader. Their purpose was to hunt down and exterminate any last vestiges of the Jedi Order. The Inquisitorius operated for many years targeting fringe Jedi that had initially escaped the Purge such as Eeth Koth, whom Darth Vader personally executed.