Anzat was discovered by the Republic fairly early, but was avoided because, if you missed it, its residents ate people's brains. Eventually the Anzati built some spaceports so they could trade with the rest of the Galaxy. Also, so they could lure people there and then eat their brains. Anzat had a history of siding with various Sith Empires and bad guys, probably because they liked killing people. And eating their brains.