The droideka (a compound word combining the Basic word "droid" with the Colicoid suffix eka, meaning "hireling" or "drone"), also called the destroyer droid (destroyers for short), wheel droid, roller, or rollies in clone trooper slang, was a type of heavy battle droid used by the Trade Federation and the Confederacy of Independent Systems. It gained a reputation for deadliness over the course of the Clone Wars. Droid commanders such as General Grievous favored the droideka for its resilience and firepower, as well as the fear it could instill in even the most powerful Jedi. They were also used for executions. They were deployed in many battles over the course of the Clone Wars, such as Muunilinst, usually in moderate numbers due to their cost, and were also used as guards in various Confederate installations. Trade Federation and Confederate Navy also utilized droidekas as security droids aboard their ships. After the Clone Wars, remaining droidekas fell into the hands of a variety of factions such as smugglers and criminals.
- "Droidekas are fast… very fast."
- ―Urai Fen
The droideka was designed by the carnivorous Colicoids of Colla IV, who were displeased by the limitations of Baktoid Combat Automata's basic B1 battle droids, and chiefly manufactured on their homeworld. The Trade Federation traded rare meats to the Colicoids as a way to ease bargaining with the ravenous insectoids, and were able to enjoy special rates on these normally very costly droids. So by cutting down the costs of these battle machines, the CIS was able to get shipments of them by the hundreds.  Before the Federation's defeat following their Invasion of Naboo, these droids were usually slaved to a central control computer. This technique fell out of favor in the aftermath of said battle, however, and they would later function independently like the B2 super battle droids did. Even before that time, the droidekas on Colla IV were not slaved to a central computer, this independence rendering them both much more expensive and much more lethal. What also made them unique to battle droids was that they could roll into position on the battle field and act as a turret. Due to their construction and design, they were over 200 times the cost of a regular B1 battle droid.
They were more formidable than the Federation's more numerous battle droids for several reasons. They were able to transform into a "wheel" configuration, allowing rapid movement and compact storage. When they encountered their targets, each of the bronzium-armored droidekas would unfold into a tripodal weapons platform, armed with a set of two twin blaster cannons which could unleash a withering torrent of firepower, though some were equipped with a blade weapon on one of the arms, such as a buzzsaw or a vibroblade.  Often, they were also equipped with deflector shield generators. These personal energy shields projected could endure much punishment, capable of deflecting or absorbing virtually any manner of energy or projectile fire up to the level of a light artillery bolt, as well as rebuffing lightsaber blades and physical attacks. The shields were powered by a starship-class fusion generator housed in a bulb at the junction of the droideka's legs. However, there was a weak point at the very top of the shield, a point where lightsabers would be able to penetrate. Many Jedi took advantage of this weak point, and it was the most commonly used method of dispatching them in the Clone Wars.  Additionally, the effectiveness of these droids was bolstered by their lack of the usual requirement for photoreceptors; instead, droidekas utilized non-visual composite radiation sensors, less likely to be distracted by light-based effects.
Droidekas were used before Naboo in the Trade Federation's attempt to annex Alaris Prime and expel the Wookiees attempting to colonize it, but the Wookiees, with the intervention of Jedi, were able to repulse the Trade Federation forces.
The Trade Federation utilized large numbers of droidekas during the Invasion of Naboo, where they proved highly effective against Naboo forces. They were used to great effect against two Jedi—Qui-Gon Jinn and Obi-Wan Kenobi—on the flagship Saak'ak, where just two of them forced the Jedi to flee. They were also used during the Battle of Grassy Plains, where they massacred Gungan warriors and were responsible for destroying the Fambaa shield generators. However, they were disabled when Anakin Skywalker took out the Droid Control Ship. After the crisis, the Galactic Republic obtained some droidekas from the reparations given to the Trade Federation, and used them onboard Outbound Flight as security enforcement, and would be obtained by the Vaagari by this way.
After the Trade Federation joined the Confederacy of Independent Systems, droidekas became mass-produced in Separatist droid foundries and were a common element of the Confederacy armies. They were used in the initial Battle of Geonosis, where most of them were stored aboard core ships which were hence unavailable for the battle, although they were used heavily in the arena stage of the battle. Over the course of the war, they proved extremely effective against enemy clone troopers and Jedi Knights, with even Obi-Wan Kenobi bearing scars from them; they posed a challenge even to elite Republic soldiers such as Delta Squad, as proved aboard Prosecutor.
They were also sometimes used as bodyguards for high-ranking Separatist figures such as San Hill. However, they met their match in the JK-13, which was not brought into mass production as the Jedi feared it would be. Indeed, the mere presence of droidekas was enough to make Jedi or other enemy forces retreat or surrender. During the Battle of Cato Neimoidia near the end of the war, squads of droids pinned down a group lead by Anakin Skywalker and Obi-Wan Kenobi, and were only destroyed by an artillery strike.
An unusually large concentration of droidekas were used in the assault on Coruscant, where they were repulsed by Yoda. In the same battle, droidekas also formed part of the team that captured Anakin Skywalker and Kenobi aboard Invisible Hand, although the Jedi exploited a weakness in their shields during the firefight on the bridge.
- "Yes, the so-called 'destroyer droids' used by the Trade Federation during the Clone Wars. The Empire has a stockpile of the droids and has reprogrammed them to guard various installations across the galaxy, including a research station and the mine here on Lok. The droidekas are programmed to attack anyone who shouldn't be there."
- ―Sergeant Moore
The remaining droidekas were purchased by the Corporate Sector and other organizations, such as the Galactic Empire. By the time of the Yuuzhan Vong War, a few system security forces still utilized droidekas. Droidekas were also used by colonies on undeveloped worlds in Wild Space as perimeter guards at night to guard against native predators. In 19 BBY, Droideka's were used by stormtroopers against Jedi Fy-tor Anna. Some fell into the hands of smugglers and criminals, and the Vagaari managed to obtain at least one unit. During the early years of the Galactic Empire, many droidekas were used by Gizor Dellso in the Battle of Mustafar. All were destroyed when the Empire bombarded the planet. One was repaired by Osaji Uhares during the Galactic Civil War. Around this time, six modified Droidekas were used as the leaders of security squads in Aucellis Park, an entertainment park that was located on the moon Keriba VI. In about 12 ABY, the renegade Jedi Dal Konur obtained some droidekas from a warehouse on Wayland and he deployed them on Bilbringi.
Tyber Zann and Urai Fen managed to capture an abandoned clone war era droid factory on Hypori from the automated security droids protecting it. A large Hutt Cartel force including Jabba Desilijic Tiure and Bossk (who was quickly bribed into defecting,) had set a trap for the two crime lords, but Urai was quickly able to reprogram the Destroyer Droid MKII security force to respond to Tyber, and managed to force Jabba to retreat. After taking Hypori Zann established many facilities devoted to the manufactore of the these droids to be used as heavy support units for the disruptor-armed infantry of the Zann Consortium.
Due to the strength of their blasters and their built-in shields, droidekas proved to be a serious threat to Jedi, especially when in groups. A few years before the Yuuzhan Vong War, Luke and Mara Jade Skywalker encountered a droideka aboard the remains of the Outbound Flight Dreadnaught-class cruisers. Even though it was decades old and not operating at its best, the two still had a difficult time defeating it. However, this version had some interesting additions, one of which was the ability to fire its blasters while in rolling configuration.
- "Data shows that the standard droideka was made with one design flaw: the shields must maintain a continual supply of energy, which may result in an overload if battered enough."
Despite being a formidable droid, the droideka had one major design flaw. Its shield was designed to enclose the droideka in a standing position, but if the droid was to be knocked on its side or against a wall, the shield would have no way of distinguishing the wall or floor from a blaster bolt or lightsaber. This meant that the shield generator had to continue supplying energy to the shield, resulting in an overload, as demonstrated during the rescue on the Invisible Hand. The shorted-out shield generator would leave the droideka vulnerable. Also, in the rolling position, the droideka's shield could not be activated, leaving it vulnerable while rolling from place to place. This technique was demonstrated by Republic Commandos infiltrating a Separatist core ship during the Battle of Geonosis and later by Anakin Skywalker and his padawan during the Battle of Christophsis. Also their shields were substantially weaker behind the droid, making them relatively easy to take out from that position. They also apparently seemed to be vulnerable to Force techniques, as Obi-Wan Kenobi used several to knock out approaching droids (and even slow down General Grievous) on board the CIS superbattleship Malevolence.
Droideka shields were ineffective against slow rolling objects, such as thermal detonators which could be rolled in and detonated. This was taught to the Onderon rebels by Captain Rex during the Clone Wars. During the Ringo Vinda campaign they were manipulated by the force and taken down with shields up by an Electro Magnetic Pulse grenade. They also showed little, if any, ability to stop strong explosions as demonstrated when CC-5576-39 encountered them and targeted various barrels of rhydonium in order to destroy them. At the Geonosis arena they were destroyed by Low Altitude Assault Transports with little to no shield resistance.
Droidekas were known to have a hard time maneuvering on downward slopes and climbing up stairs. In their rolling configuration, they would have to go back quite a bit and then speed up, launching themselves up the stairs. They could also try to traverse stairs in walking configuration, although it was extremely hard for them to coordinate their three legs on stairs. In their standing position, they could not move very fast, forcing them to roll over long distances.
Additionally, there were limits when a droideka could fire at a target. If the target got very close to it, the droideka would miss its shots because its blaster arms were spread out. This also enabled an enemy to run around it while attacking. 
Droideka series and variantsEdit
There were three known series of droidekas. They were outwardly similar; the differences were mostly internal. The first, the P-series droideka, was used in the Invasion of Naboo in 32 BBY. The W-series droideka was used in the Battle of Geonosis in 22 BBY. Later, the Q-series droideka was used aboard the Invisible Hand to capture and trap Jedi master Obi-Wan Kenobi and Jedi Knight Anakin Skywalker in 19 BBY.
Five known variants of droideka existed. The first was the grapple droideka, used around the time of the Invasion of Naboo. It was equipped with electronic grapples and was designed for melee combat, and lacked blasters. It also seemed to possess weaker shields than average.
A third, the droideka Mark II, would see action on the battlefields of the Galactic Civil War. This model had four stubby legs, an ion cannon, and was larger than the Separatist models. Since the plans for it were discovered on the old Separatist droid-producing world of Hypori, it may have been a dropped CIS project. It would be employed by the Hutt Cartel briefly, then quite extensively by the Zann Consortium.
A fourth droideka variant was the K3-I Buzzer Droid used also during the Galactic Civil War. This variant was used on Station Gamma above Ord Mantell. It was weaker than an average droideka and lacked shields.
A fifth droideka was sniper droideka, which was used by the CIS during the Clone Wars. It included a sniper rifle in its head, in addition to the rest of its weapons. The CIS deployed at least two Sniper droideka during its invasion of Kiros.
Behind the scenesEdit
According to the DVD commentary of The Phantom Menace, a droideka's blaster is meant to sound similar to those of an All Terrain Armored Transport. This is adhered to in the Episode I game and Jedi Power Battles games.
In the 2001 video game Star Wars: Galactic Battlegrounds and its 2002 expansion pack, destroyer droids are the Trade Federation special unit. They are produced at Trade Federation fortresses for a cost of 50 units of carbon and 150 units of nova crystals. Only the upgraded heavy destroyer droid uses shield generators.
Strangely enough, droidekas do not seem to ever use their shields in Attack of the Clones, Star Wars: Clone Wars and only briefly in Revenge of the Sith. This made them more open to attacks, a feat that was exploited by Clone troopers and Obi-Wan Kenobi. This is because these are W-series droideka, which have more powerful blasters, at the cost of less energy to operate the shields, resulting in the shield being rarely used. This weakness was resolved in the Q-series droideka, which had both powerful blasters and plenty of energy for the shields. The original model, the P-series droideka, had weaker blasters and a slightly less efficient shield than the Q-series.
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