Appearance: The Gunhawks #1 (October 1972).
Appearances: The Gunhawks #1-6, Blaze of Glory #1-4.
Years Active: 1860s-1885.
The son of a Southern plantation owner and slave owner, Kid Cassidy teamed up with Reno Jones, who had been owned by Cassidy's father, to become "the Gunhawks". After the Civil War the pair wandered around, having adventures, with Cassidy feeling sorry for himself (he was from the South, and the South got beat in the Civil War, so of course he's going to feel sorry for himself). Kid Cassidy was originally killed in Gunhawks #6.
Blaze of Glory depicts a more realistic Kid Cassidy, one who grew meaner as he grew older and seemed to have been killed by Reno Jones, although he survived to threaten the town of Wonderment before finally being killed, again, by Jones; see Jones' entry for more detail on this.
Note: My sympathies in the matter of the Civil War should be obvious. I'm opinionated, certainly, but The Gunhawks really is an embarassingly-poorly written series.