Smiting
The power attack, cleave, and great cleave abilities were just so that he could get in there and kill a few dozen enemy soldiers before he has the climactic one-on-one duel with the enemy commander in which he (hopefully) cuts off the commander's arms and beats him to death with them.
The undying devotion ability only works on followers and cohorts, who only number 1000 or so (even with this PrC), it does not encompass all of his troops and thus he probably could not make an entire army out of them, a pretty fair mercenary troop, but not an army.
I didn't include any save vs. fear or any specific bonuses to strategy or tactics, save very general ones to attacks and all saves, since I'm not sure what system of mass combat will be used by those that take the class.