If Disney needs a model for their next animated villain, Dr. Flint would be a good contender. He's cruel, capricious, malevolent, and just plain creepy. We don’t hear him speak very much—most of his dialogue is second-hand—but we get a perfectly clear picture of him from his actions. Take, for example, this early description:
Dr. Flint was an epicure. The cook never sent a dinner to his table without fear and trembling; for if there happened to be a dish not to his liking, he would either order her to be whipped, or compel her to eat every mouthful of it in his presence. (2)
Is this clear enough? He takes pleasure in food, but he seems to take more pleasure in violently enforcing his will on his servants.
Later on, Linda gets more explicit, painting an unlovely picture of her master:
He was a crafty man, and resorted to many means to accomplish his purposes. Sometimes he had stormy, terrific ways, that made his victims tremble; sometimes he assumed a gentleness that he thought must surely subdue. Of the two, I preferred his stormy moods, although they left me trembling. He tried his utmost to corrupt the pure principles my grandmother had instilled. He peopled my young mind with unclean images, such as only a vile monster could think of. I turned from him with disgust and hatred. But he was my master. I was compelled to live under the same roof with him—where I saw a man forty years my senior daily violating the most sacred commandments of nature. He told me I was his property; that I must be subject to his will in all things. (5)
Here, we learn that Dr. Flint is crafty—and later on, we get proof of this when he repeatedly tries to trick Linda into reading his letters, or sneaking off to his love nest, or believe that his son rather than he is writing to her.
We also learn that he's got a temper, and that, as she says later, he's "willful and arbitrary" (7). This is the picture of a man who is totally corrupted by the absolute power he has over his slaves. Would he have been so nasty if he hadn't had power of life or death over Linda? It's impossible to know for sure, but Linda definitely implies that the system of slavery doesn't bring out his good side.
So, we've got absolutely no sympathy for Dr. Flint. Really, who could? But there's a hint in the novel that it's not all his fault. Linda more than once says that slavery corrupts white and black people alike—"The slaveholder's sons," she says, "are, of course, vitiated, even while boys, by the unclean influences every where around them" (9). If Dr. Flint's father was harassing slave girls, then it's not so surprising that Dr. Flint does, too.