The Athran Brotherhood
Sometimes calling itself the "The Scions of Athra," the Athran Brotherhood is a group of Khanid secessionists with headquarters located on the Khanid homeworld of Amarr Prime (called Athra in the Old Khanid tongue). This group tends to rise perhaps every other generation or so, seemingly from its own ashes, making trouble for local government and interstellar trade alike.
Given the many large pirate organizations and other independent "freebooters" of New Eden, not to mention the constant weight of intergalactic politics and the ongoing "Minmatar Problem," Amarr rulers cannot generally spare a large-scale military effort to deal with these relatively minor troublemakers. Perhaps this is the reason the Brotherhood seems never to die, but always reappears just when authorities start to think they've rid themselves of the nuisance.