The JMM assassin droid represents a specific type of assassin and espionage droid manufactured during the time of the Galactic Republic.
A JMM unit's head possessed a weight of ten kilograms.
The droid known as 8t88, an information broker, became the victim of a practical joke that involved replacing his head with that of a JMM droid. This head was severed and subsequently consumed by his pet, Grendel. Kyle Katarn eventually recovered it, extracting the coordinates of the Valley of the Jedi that were stored within its memory. During this endeavor, he employed the droid's head as a weapon against Pic, who was attacking him; the impact propelled Pic into a bulkhead with such force that he died instantly.
Following an accident that resulted in the loss of his own limbs, Imperial Grand Moff Bertroff Hissa received the arms of a JMM droid as replacements.
In Kyle Katarn's Tale, the initial reference to this droid characterizes it as an espionage droid. Conversely, both The Complete Star Wars Encyclopedia and Barely Tolerable: Alien Henchmen of the Empire classify it as an assassin droid.