A Jedi hunter, alternatively referred to as a Jedi killer, was a person whose job it was to hunt down and kill individuals belonging to the Jedi Order.
The Children of the Storm were once Force-sensitive individuals who had been experimented upon by Baron Boolan. They functioned as Jedi hunters during the Nihils' control of the Occlusion Zone. A component of their objective was to seize additional Force-sensitives for further experimentation. Certain Nihil, under the command of General Abediah Viess, also took on the role of Jedi hunters.
General Grievous, the Kaleesh Supreme Commander of the Separatist military, received training in lightsaber combat from Count Dooku. He would then claim the lightsabers of the Jedi he killed as trophies. As the Clone Wars continued, Grievous developed a terrifying reputation as a skilled Jedi killer, instilling fear in the Republic's populace. Among those he killed were Neebo, Nahdar Vebb, a Mikkian Jedi, and a human Padawan.
Bounty hunters were sometimes hired to be Jedi hunters; Cad Bane, for instance, was known to have killed Jedi during the Clone Wars.
After the transformation of the Galactic Republic into the first Galactic Empire, the Inquisitorius was established. This organization of Jedi hunters was trained by Darth Vader to use the dark side of the Force and wield double-bladed spinning lightsabers to assist the Empire's extermination of the Jedi. Emperor Palpatine mandated that captured former Jedi Order members must either be converted into Inquisitors or killed. This further contributed to the fall of the Jedi religion and the corruption of the Force.
Ochi of Bestoon, a Sith cultist and assassin, was a Jedi hunter who battled Jedi Masters Depa Billaba, Mace Windu, and Luke Skywalker in separate confrontations. He was dispatched to assassinate Sidious's Sith apprentice Darth Vader, and managed to put up a fight against the injured Sith Lord and former Jedi Knight.