What did the KKK do to black people?

The objective of the Ku Kux Klan, and other white supremacy groups, was to terrorize blacks into a secondary or subservient role. This was intended to prevent blacks from gaining wealth, authority, or elective influence. In times of economic hardship, they were determined to have employment opportunities and government that favored whites. Accustomed to blacks as slaves, they did not relish having them as equals, or as masters.

Violence by the the Ku Klux Klan took the form of shootings and cross-burnings to intimidate the black masses. They were also fond of a method of torture called "lynching". They would not only hang the blacks, but would storm their houses and drag them from their beds in the dead of night to do so, often in front of their families. They would murder as many as they needed, to maintain their atmosphere of terror.