Fistful of Frags probably is the first western game where cowboys were chased by crazy axemen. AI controlled axemen will be present in this new game mode, as some sort of basic class. If rattlesnake is special ops, dynamiter is artillery and whiskey guy is medic, axeman is infantry ^^.
Its behavior is as simplistic as you would expect from someone handling a short axe against armed guys. Unlike the rattlesnake, axemen can be spotted easily and that's an inconvenience or advantage depending what you want from them. A frontal attack isn't very wise, but may attract enough attention for a surprise attack coming from other direction.
The video shows 2 different situations where an axeman acting as decoy will help another mate coming from behind. For this purpose, extra health is given to decoy while the other NPC gets extra speed and damage to deal with enemies as quick as possible. There's a variation of this tactic using an explosive barrel, which axeman is able to use as projectile if the special skill is assigned. That barrel has alone other interesting uses and possibilities, of course.
1. FPS hybrid, our next little thing (introduction).