I'm sorry, you have not provided the passage in question. The most notable mention of Mr. Severe is as follows;
Mr. Severe, the overseer, used to stand by the door of the quarter, armed with a large hickory stick and heavy cowskin, ready to whip any one who was so unfortunate as not to hear, or, from any other cause, was prevented from being ready to start for the field at the sound of the horn.
Mr. Severe was rightly named: he was a cruel man. I have seen him whip a woman, causing the blood to run half an hour at the time; and this, too, in the midst of her crying children, pleading for their mother's release. He seemed to take pleasure in manifesting his fiendish barbarity. Added to his cruelty, he was a profane swearer. It was enough to chill the blood and stiffen the hair of an ordinary man to hear him talk. Scarce a sentence escaped him but that was commenced or concluded by some horrid oath. The field was the place to witness his cruelty and profanity. His presence made it both the field of blood and of blasphemy. From the rising till the going down of the sun, he was cursing, raving, cutting, and slashing among the slaves of the field, in the most frightful manner. His career was short. He died very soon after I went to Colonel Lloyd's; and he died as he lived, uttering, with his dying groans, bitter curses and horrid oaths. His death was regarded by the slaves as the result of a merciful providence.
Mr. Severe's place was filled by a Mr. Hopkins. He was a very different man. He was less cruel, less profane, and made less noise, than Mr. Severe. His course was characterized by no extraordinary demonstrations of cruelty. He whipped, but seemed to take no pleasure in it. He was called by the slaves a good overseer.
The central idea revolves around the cruelty of slavery, and the theme it best represents would be the perversity of slavery.
