BT - 1 BT - 1 , also referred to as " Bee Tee , " was a homicidal BT - 1 assassin droid created by the Galactic Empire ' s Tarkin Initiative . After being found and reactivated by Doctor Aphra , BT - 1 and his fellow droid 0 - 0 - 0 served under Lord Vader . Biography . Before activation . BT - 1 was designed to look like an astromech droid in order to fool others , and was armed with a variety of weapons . He killed the staff of the Tarkin Initiative base in which he was created and then continued to set the base to self - destruct before jettisoning himself into space . He was found by the rogue archaeologist Doctor Aphra , who could not reactivate the assassin droid as she could not speak the R & D language the droid was programmed to understand . After Aphra reactivated the protocol droid 0 - 0 - 0 , a droid capable of understanding the language , she had the protocol droid reactivate BT - 1 . Instead of giving the two droids to the Droid Gotra , as she had originally been hired to do , the archaeologist put them in the service of Sith Lord Darth Vader , who had tracked Aphra down to demand her services in creating a personal army for himself . Serving Darth Vader . Cylo - V ' s replacements . BT - 1 accompanied Aphra and Vader , together with 0 - 0 - 0 , for their mission on Geonosis , where Aphra had heard of a Geonosian queen who was in control of a droid factory . The four invaded the queen ' s factory , stole the machine that constructed droids and quickly escaped . Not much later , a bounty hunter that Darth Vader had earlier hired , Black Krrsantan arrived , with Cylo - IV , a person who Vader was suspicious of . Vader ordered 0 - 0 - 0 to interrogate Cylo - IV and when 0 - 0 - 0 believed that he had extracted all information he could , he killed him . 0 - 0 - 0 told Vader that Cylo - IV was training the Emperor ' s possible future replacements for Vader and the Dark Lord set course for Cylo - IV ' s research base . To start off his attack , Vader sent BT - 1 and 0 - 0 - 0 into the base as distractions . He then proceeded to attack Cylo - IV ' s men from behind , with his small army of droids . As he continued into the base , Vader found two twin humans , one male and one female . The twins attacked him , using lightsaber s , however it was clear to Vader that they weren ' t Force - sensitive . After a quick fight , the two humans were told to stop by Cylo - IV , who revealed that he was an immortal system that switched to a new body as soon as the previous was destroyed and that his current body was called Cylo - V . Cylo - V introduced his replacements for Vader and as Vader was about to strike Cylo down , the Emperor revealed himself to be in their presence and asked to see what Cylo ' s replacements were capable of . Cylo started by showing off the twins from before , named Aiolin and Morit Astarte . He continued to show the rest of his warriors , until he decided to show their abilities by having them all fight each other to the death . Vader started by fighting against an enhanced Trandoshan , but in the middle of their fight , Morit killed the Trandoshan . Sidious stopped the fighting , wanting to use them against his own enemies instead of each other . Vader left Cylo ' s research station and waited for Boba Fett , the bounty hunter he had hired to find the person responsible for destroying the Death Star . Fett told Vader that he had found the person and that the two briefly fought , with the latter winning . Fett had figured out that the person was named Luke Skywalker . Vader ' s son . Sometime later , Vader instructed Aphra to join up with a group of bounty hunters and plunder an Imperial ship for credits . After sharing the credits between each other , the bounty hunters parted ways . Vader then sent Aphra to retrieve information on Commodex Tahn , the person who buried Padmé Amidala , as Vader wanted to confirm that Padmé gave birth to Vader ' s son before dying . Aphra , 0 - 0 - 0 and BT - 1 went to The Ante an information broker , on the Spire , who after being paid a large amount of credits , gave the three information about Tahn , including the fact that he lived on Naboo . Thereafter , they attacked Tahn ' s home with some of Vader ' s droids and then subsequently tortured and interrogated Tahn , until he confirmed that Padmé had indeed given birth to a boy , after which 0 - 0 - 0 killed him . Aphra , 0 - 0 - 0 and BT - 1 soon returned to the Ante , seeking information on Luke Skywalker ' s location , while BT - 1 and 0 - 0 - 0 went to play holochess . The Ante quickly figured out that Aphra was one of the plunderers of the Imperial ship carrying credits , after seeing the amount of credits she was ready to give , but still gave the location of Luke . The Spire was soon attacked by Imperials who believed that one of the plunderers were there . After quickly interrogating the Ante , the Imperials learned that Aphra was one of the plunderers from before . Aphra , BT - 1 and 0 - 0 - 0 escaped the Spire , before finding themselves locked in by an Imperial blockade . Darth Vader , who was on one of the blockade ship and could not reveal that he was working with Aphra , was able to convince Inspector Thanoth that they were wasting their time chasing a thief , when they could instead attack the recently discovered base of a Rebel Alliance squadron . With the blockade gone , Aphra met up with Vader again and told him that Luke was located on Vrogas Vas . Before finding Luke , Vader took BT - 1 and 0 - 0 - 0 with him to ore - rich planet of Shu - Torun , where both the ore - duke s and the ruling family were slowly rebelling against the Imperial control . While Vader was taken to a celebration party with Prince ss Trios , the two droids went to assassinate the king and his servants . When Vader and Trios found the dead bodies , Vader informed Trios that from now on , she would become the Queen of Shu - Torun and warned her that if the planet kept resisting the Empire , consequences would follow . Vader then sent BT - 1 and 0 - 0 - 0 back to Aphra , while he set course for Vrogas Vas . Vader kept contact with Aphra as he arrived above the planet , but not soon after arriving , he was attacked by Rebel Alliance ships . Aphra listened as Vader ' s ship crashed and decided to go and save Vader , with 0 - 0 - 0 and BT - 1 . After landing on the planet , they found Luke Skywalker and his astromech droid R2 - D2 . In order to trick Luke , Aphra painted 0 - 0 - 0 yellow and tricked Luke into believing that he was C - 3PO , one of Luke ' s allies . 0 - 0 - 0 was able to get near Luke and shock him with electricity , making him fall unconscious . When he saw that he stood no chance against BT - 1 , R2 ran away , with BT - 1 not far behind , following him . Aphra and 0 - 0 - 0 were eventually found by Han Solo and Chewbacca who demanded they let Luke go . A fight between the four broke out , while Luke was still unconscious . R2 soon found Luke again , who was now conscious and the two outran BT - 1 . BT - 1 then regrouped with 0 - 0 - 0 , who had lost both his arms , one pulled off by Chewbacca , one by Luke and found that Aphra had fallen unconscious in the fight against Han . The two droids got ready to eradicate Luke , Chewbacca , Han and R2 , but as BT - 1 got his weapons ready , R2 sprayed oil on him , blinding BT and resulting in him shooting everywhere , giving time for the others to escape and trapping the two droids under rubble . As soon as Aphra woke up , she helped the droids out of the rubble and ordered the droids to find and secretly follow Luke . The two soon found C - 3PO , whose arms 0 - 0 - 0 took , reattached on himself and left him . Arrival of General Karbin . When 0 - 0 - 0 and BT found Luke , they saw that he was fighting Imperial troops , however they knew that Vader didn ' t take any troops with him . They were then contacted by Aphra who told them that General Karbin , one of Cylo - V ' s replacements for Vader , had arrived on the planet to capture Luke for himself . Aphra told the droids to protect Luke from the Imperial troops in any way possible . Their protection wasn ' t enough , as Luke was captured by Karbin anyway . Luke was taken aboard Karbin ' s ship , as Vader watched it fly away . Not wanting to accept Karbin ' s victory , Vader used the Force to crash the ship . Luke was found again by Han , Chewbacca , R2 and 3PO , before the group was approached by Aphra , who informed the group that they were standing on a minefield and threatened to kill them all if they didn ' t allow themselves to be captured . As they began dropping their weapons , Leia knocked Aphra unconscious from behind . The rebels took Aphra with them on their ship and left the planet . Further trouble on Shu - Torun . After delivering Karbin ' s dead body to his master , Vader was ordered to accompany Cylo - V and his warriors for their return to Shu - Torun , after the resistance on the planet became too unbearable . After arriving on the planet , Vader met with bounty hunters Black Krrsantan , Zuckuss , IG - 90 , Dengar , Chanath Cha , Beebox and C - 21 Highsinger and told them to find and return Dr . Aphra to him . Not much time went by before Beebox returned to Vader with a disintegrated body , claiming that he had killed her , however Vader quickly saw through Beebox ' s lie and killed him for it . While Vader was away , 0 - 0 - 0 and BT - 1 gave some of Vader ' s droids the ability to leech blood , despite Vader ' s orders not to . The droids used this ability in their battle against Baron Rubix ' s soldiers , easily making their foes surrender out of fear . Vader soon learned of the two droids ' actions , but had no time to care , as he had to use this chance to attack Rubix ' s citadel . After the execution of Rubix , Vader and his droids left it up to Queen Trios to defeat the now - weakened rebellion on the planet . Arriving back on a Star Destroyer , Vader explained to his two droids that before the attack on Rubix ' s citadel , Vader had been attacked by Cylo - V ' s two twin warriors , Aiolin and Morit , and that Morit had killed Aiolin in the fight . He also told the two that Cylo - V and the rest of his warriors had revealed themselves to be traitors , as they had aided the ore - dukes . Vader reported to his master , who ordered him back to Coruscant , as Sidious wanted to explain everything going on with Cylo - V , but before leaving , Vader was contacted by Thanoth , a former inspector and traitor of the Empire , who informed Vader that he had found Aphra . Personality and traits . BT - 1 was originally programmed by the Tarkin Initiative to be violent and cruel . After being reprogrammed and having his behavior changed by Aphra , he was no longer rogue and was able to be commanded . He mostly follows 0 - 0 - 0 and possibly considers him a friend .