The entity known as the "Jedi killer" was a type of droid responsible for the demise of several Jedi on the planet Cularin. Ultimately, the Jedi brought its rampage to an end, but the confrontation resulted in widespread destruction in Hedrett, with buildings collapsing and city blocks being obliterated, even impacting the sewer systems.
During the conflict with this droid, Devan For'deschel sustained injuries. Minos Fel'Kona drew a comparison between the droid and the tactics of General Grievous, noting similarities.