Answer:
The central idea of Narrative of the Life of Frederick Douglass is slavery, and how it affected not only slaves but also slavesholders.
Step-by-step explanation:
In this autobiography, Douglass reflects the inhumanity and suffering of the treatment received by the slaveholders.
Their main theme is slavery, and how slaveholders were cruel and inhuman with them, letting themselves be carried away by their power over black men. An example of this is the case of Sophia Auld, who despite being tender and sweet with him in the beginning, ended up being carried away by power and becoming a true demon.