Then there's the fellow whose cousin or uncle was convicted for violating the Runaway Slave Act ~ I think he got involved in the Jay-Hawk War before the big one.
One of these poor fellows married a woman whose family owned Southern Maryland (for the most part) and just about everyone who lived there. They had 8 to 10 kids ~ but while he was away at war she ran off with a slacker who rode with Morgan's Raiders. His name was Cheney ~ and he ended up taking her to live with his family in Lincoln, Nebraska.
So, you just never know who's a Yankee and who isn't.
Seriously, I don't know of any of my ancestors who fought in the Civil War, of whom were in America were all Northerners (none of my relatives were in the South at that time, the last one, a North Carolina-born Scots-Irish having moved to Illinois from Tennessee after serving under General Jackson at the Battle of New Orleans). The earliest direct ancestor of mine in the U.S. was one of those paid Hessian mercenaries hired by the British during the Revolution, of whom made a rather bold decision to stay in America after the war was over. Most of his comrades who also chose to stay were not so lucky, as the majority of them were hunted down and murdered by New Jersey patriots following the war.