Cashel McCogan was created by Scott Snyder and Rafael Albuquerque. He first appeared in American Vampire #6 and participated in the story arc ''Devil in the Sand''.
Major Story Arcs
Devil in the Sand
Cashel had a pregnant wife and was investigating murders that occurred in Las Vegas. Three people were responsible for building a dam in the city and the assassin - which we later find out that is Cashel's father (who belongs to an old species of vampires) - is killing each one of them. Later on in the arc, his father is killed, ending his vampire bloodline, and Skinner Sweet abducts Cashel's wife, who is pregnant. He threatens to turn her into a vampire, but is stopped..
After his run-in with Skinner Sweet in Las Vegas, his wife has died and his child has been injected with vampire serum (making him the third "American Vampire" that we know of. With the drive of trying to find a cure for Vampirism he join the group of Vampire hunter and teams up with Felicia Book for a journey into Nazi Germany.