JK-23 was originally produced to infiltrate the Jedi Academy on Ossus but by the time he was completed the New Jedi Order appeared to be on the decline and the heads at Loronar decided to hold off sending in another valuable JK-unit. They instead used JK-23 on other missions across the galaxy that had a financial interest to the company. It was during one of his routine missions that JK-23's independent streak grew and he tired of his arrogant masters at Loronar using him for the menial tasks of assassinating politicians that were of no importance to him. He desired to hunt and kill for that which he was created, Jedi. JK-23 returned from his errand and promptly executed his handler. The heads at Loronar attempted to send other JK-units in to deactivate JK-23, but this backfired as the other units found that they could not kill one of their own and a full scale revolt broke out. The JK-units received heavy losses but a good number of them, including JK-23 escaped.
Free to pursue his own goals, JK-23, began to track down and hunt Jedi throughout the galaxy, occasionally taking odd jobs to help finance his endeavours. He was extremely successful in eliminating targets but his aggressive nature often times resulted in unnecessary destruction. It was reported once that he shot a photon missile into packed nightclub on Coruscant just to eliminate a target that he had grown tired of pursuing. This high level of recklessness resulted in only the most vile of crime lords actually even considering his employment. This was satisfactory to JK-23 as when his services were needed they were mostly from desperate clients from whom he could extract high payments.
JK-23's programming was similar to HK-47's misanthropic views. He detested the 'meatbags' that surrounded him and was only slightly tolerant of a few sentient beings that either served a use to his long term goals of collecting Jedi trophies, were strong warriors like himself, or possessed enough credits to make him forget about his disdain for them.
He is ferociously independant, having only considered a few people as partners. He had been known to refer to a few people as 'master', but most of the time it was a ploy to use someone.
Due to JK-23's original design to be used to infiltrate the Jedi Academy on Ossus, his armor plating was a dark forest green color to help blend into the jungle surrounds of the planet.As was the case with all JK-units, JK-23 was designed to fold up and conceal himself inside of a false droid frame. He typically uses an R6 frame and has adjusted most of his programming to simulate the basic functions required of this model to pass himself off. He was also one of the few JK-units that was designed to interface with a larger exo-skeleton frame known as a Tank Frame to be used in situtations that required more brute force, although his exo-skeleton had been left behind when he fled the Loronar Corporation and has never recovered it.