What was the purpose of the Ku Klux Klan?

The KKK wanted an Aryan race that did not include blacks, Hispanics, or any other race different in color. It was against different churches (other than their own), people such as the Jews or Catholics, or any race that was white but not of the KKK's following.

At first the main objective of white supremacy organizations such as the Ku Klux Klan was to stop black people from voting. After white governments had been established in the South, the Ku Klux Klan continued to undermine the power of blacks. Successful black businesses were attacked, and any attempt to form black protection groups such as trade unions was quickly dealt with.

Thankfully the KKK membership has dwindled to a few thousand.