It's KU Klux Klan...not KLU even though they don't have a KLU (ooo that's bad. he he)
Seriously though, the Ku Klux Klan was formed as a social group in Tennessee in 1866. The name probably came from the Greek word kuklos, meaning "circle."
Klan was an alliterative version of "clan," thus Ku Klux Klan suggested a circle, or band, of brothers. With the passage of the Military Reconstruction Acts in March 1867, and the prospect of freedmen voting in the South, the Klan became a political organization. Former Confederate general Nathan Bedford Forrest probably served as the Grand Wizard, or overall leader, of the Klan and certainly played a significant role in its organized spread in early 1868.
And as Paul Harvey says, "Now you know the REST of the story."
As far as the KKK being "neo-Aztec", that's a new one on me. Neo meaning NEW or RECENT, as in NEO-NAZI. The Aztecs participated in human sacrifice and there has been a report back in 2001 of a Seattle man being killed in a NEO-AZTEC type killing...he had apparently been lured to a cleverly disguised downtown pyramid altar on the promise of gainful employment. The police said that they received a report of a feather-robed, gold-masked Aztec priest standing atop the building on Howell Street holding a still-beating human heart in one hand and an obsidian knife in the other.
This might be a cult that has been formed. No other report has surfaced that I could find.