He is recognizable by his large frame and a small mustache.
"Ever seen a soldier kill somebody? It's time to see!"
"You missin' me, you won't be risin' in the world no more."
"I never lost a fight, ever!"
"Ain't nobody gonna hurt me without getting hurt more."
"Wanna see me punchin' out a man with one hook?"
"I was born violent, just my nature!"
"Good thing I'm on the right side. I think I'm official's criminal."
"Ain't nothin' making your enemy suffer!"
"God made me a good fighter, nothin' I can do about it!"
"A darn good killer's what I am!"
He has the aspects of an American Army Officer, meaning he is the highest ranking unlockable character in Red Dead Redemption from the American Army. His shoulder insignia indicates that he is a First Lieutenant.
His first name, Jan, is a very common name in the Netherlands and Denmark, hinting that he may have Dutch or Danish ancestors.
His name may be a reference to John Booth, the man who assassinated Abraham Lincoln.
Just like Eric Morganson and the American Army Captain, Jan Booth wears boots instead of the low-ranking soldier leggings, and also wears a black hat, indicating that he's a member of the U.S. Cavalry.