Appo, also known as CC-1119, is a minor antagonist in the Star Wars franchise. He appears in both in canonical media and in the Star Wars Legends forms of media, being a sergeant and later commander of the 501st Legion.
Sergeant Appo is a member of the elite 501st Legion. His career is not explored in detail, and the only known battle he participated in was the Battle of Umbara. Here, Appo would eventually help Commander Rex, members of his own legion and survivors from the 212th Batallion to defeat General Pong Krell. The Jedi commander had turned traitor, initiating a staged battle between the two clone armies in order to ensure a Separatist victory and allow him to defect. Appo was present when the General was executed.
Towards the end of the war, Commander Rex and several other members of the 501st were reassigned to aid Ahsoka Tano as part of a new clone division, at the request of the famed Republic General Skywalker. With their Commander away, Appo was promoted and took over command of the legion.
This meant that Appo, alongside many of his brothers, was present on Coruscant when Order 66 was given by Emperor Palpatine. He accompanied General Skywalker, now renamed Darth Vader, to the Jedi Temple. Under the influence of their programming/inhibitor chips, Commander Appo and the rest of the clones helped Vader to conquer the Temple. They took no prisoners and slaughtered everyone they came across.
As the conquest of the Temple neared its end, a speeder made its way towards the burning building, landing on one of the higher platforms near the Jedi hangar. Onboard, was Senator Bail Organa, representative of the planet Alderaan, and an ally of the Jedi Order. Accompanied by a small squadron Appo met with the Senator personally.
Blocking the way, the Commander informed the confused Senator that the Jedi had tried to orchestrate a rebellion but assured him that the clones now had everything under control. Unconvinced, Organa tried to enter the Temple, but Appo and the other clones raised their weapons at him, the former telling the Senator to leave. Taking the hint, Bail complied under the watchful eye of the Commander and his retinue.
As the Senator neared his speeder, however, a sudden noise took them all by surprise. Turning around, Organa saw a Jedi Padawan, Zett Jukassa being chased by a second group of clones. Taking advantage of Appo's focus on Bail, Zett landed amongst the first squad ranks, cutting down all of the clones in self-defense.
Slashed across the chest by the Padawan's lightsaber, Commander Appo was cut down alongside the rest of the clones that confronted Bail before he could react. The Commander would be avenged moments later by CT-0000/1010, who killed Jukassa before he could escape. Horrified by what he had just seen, Bail Organa fled the scene in terror, with Appo's subordinates letting him go. The sight of what he had seen, inspired Organa to begin a search for any surviving Jedi and later, to help found the Rebel Alliance.
Star Wars Legends
In the original Star Wars Legends storyline, Jukassa only succeeded in injuring Appo, rather than killing him. Once the battle at the Jedi Temple was concluded, the Commander received medical treatment before returning to active service. There, Appo became a member of the first generation of Stormtroopers.
As such, Commander Appo continued to help the Galactic Empire in establishing dominion over the galaxy. He helped to save Darth Vader from a Jedi ambush on the planet Kessel. Later, he accompanied the Dark Lord on several missions to subjugate former Separatist worlds, as well as track down renegade Jedi and clones.
Eventually, Vader and Appo met with Grand Moff Tarkin, who had tracked a group of Jedi to the Wookiee homeworld of Kasshyk. By chance, this was a group of Jedi that had evaded the Dark Lord and the Clone Commander earlier that year. With the full permission of the Emperor, Tarkin and Vader began an invasion of Kashyyk.
The Imperial forces were met fierce resistance, the ferocious Wookiees refusing to go down without a fight. As the battle grew more intense, Vader decided to enter the fray himself, with Appo leading the escort. Upon landing, the group was set upon by a group of Wookiees and Jedi. Appo managed to hold his own, allowing Vader the opportunity to slay most of their attackers. The last survivor was a Jedi Padawan called Olee Starstone. Vader told Appo to leave her to him, telling the Commander to take his troops, and deal with the Wookiees.
Before Appo could do anything however, another ship touched down, and on-board it was the Jedi Master Roan Shryne. Before the Sith Lord or Clone Commander could react, Shryne called upon the force, summoning one of the fallen lightsabers to his hand. With a single swipe, he decapitated Appo, thus avenging all the Jedi that the traitorous Commander had massacred back at the Temple. Appo’s death was subsequently avenged by Darth Vader, who was disappointed at the Commander's death.