Southern history is a wonderful thing when told honestly. We dont get that very often.
There were many more white southerners who fought for the Union than there were black southerners who fought for the Confederacy, but that fact is not well known either.
Yes there were, like my great-grandfather, a Confederate member of the 36th Virginia Cavalry, who was captured in 1862, sent to Camp Chase, Ohio, and forced to join the Union Army on a work gang under threat of death.