Explain the topic in detail: dark side of followership/leadership. Answer why followers will commit evil acts under tyrannical leadership?

Exploring The Dark Side of Followership and Leadership

My research topic is: Exploring the dark side of followership and leadership.
Three historical leaders are to be researched within paper: Joseph Stalin, Adolph Hitler, and Chairman Mao Zedong. This paper is paradoxical identifying the dark and positive sides of their leadership.

Explain the topic in detail: dark side of followership/leadership. Answer why followers will commit evil acts under tyrannical leadership?