Brutus and Natalie, the slaves/servants of widow Leila Ellis, are fictitious. But they represent what some moderns, in a simplistic good/evil dichotomy of the complicated Civil War, consider a unique Southern evil.
They probably never heard of the Northern-financed slave ships sailing from the wharves of Lower Manhattan through at least 1862. Not to mention the history of slavery in the North, or the continued restrictions on freed African-Americans living there. Independent historian Douglas Harper of Lancaster, PA, ably describes Northern slavery and its lingering effects in this site devoted to the subject.
UPDATE: Despite emancipation, the thousands of black soldiers who had fought for the Union were denied the right to march in the Grand Review of the Armies, which trooped past the White House in May, 1865, a month after Lee’s Army had surrendered.