I had one ancestor living in Missouri who served in a Union outfit--his brother was a Confederate. Another direct ancestor was a Confederate.
I just learned that a second cousin, four times removed, is one of the Union soldiers buried at Arlington National Cemetery. (Most of my relatives with his surname were Confederates, but he was from Ohio.)
On the one hand, I’m as Southern as it gets — every one of my direct ancestors was born in Virginia, North Carolina, South Carolina, Tennessee, or Europe. Not a Yankee in the bunch. On the other hand, some collateral kindred migrated to Indiana before the Civil War, and the only one of my kinsmen killed in the war to my knowledge was an officer in General Sherman’s army. My direct ancestor who “fought” for the Confederacy was a Unionist who was conscripted after several years of draft-dodging. (He fought in one battle, was wounded and captured, was nursed back to health in a Yankee hospital, then paroled and put on a ship to Georgia where he and others were exchanged for Yankee prisoners. Evidently the authorities expected him to report back to his unit in Winchester, VA, but he got off the train in the vicinity of Charlotte, NC, and walked home.)