Jesse McKines was a normal cowboy from the year 1867. He and a few other cowpokes were driving a herd of cattle to Kansas City when Jesse and his horse, Firefly, were sucked into a plothole created by a bad novel in someone's saddlebag. Jesse and Firefly ended up at HQ, and, upon seeing that the agents had beds that were not singular blankets on the ground, Jesse signed up.
Jesse is a lanky, tan man, standing at six feet even with a head of blond hair and a constant half inch or so of golden stubble. He has a charming smile, which he is quite aware of. He never goes anywhere without his trusty hat, and he is usually wearing flannel.
Jesse can be a bit odd at times, and he's very attached to his hip flask, but otherwise he's a dependable friend. He and Agent Alleb are a good pair, as they are both unfamiliar with modern technology. They are also similar in that they are both veterans, albeit from very different wars.
Jesse comes from a massive crossover fanfiction of every Western ever. Yes, all of them. He saw John Wayne under different names some twenty times in the last three years and hasn't figured out why yet.