I'm thinking of replacing Inspire Pain and Inspire Retributions' effects entirely. Marshal auras directly dealing damage is a bit odd since they're extraordinary abilities, unlike the other classes which have supernatural abilities. This means that incorporeal creatures ignore the damage, and its affected by damage reduction, too (unless its energy damage or a force effect, neither of which fit the marshal fantasy). Unlike with standard attacks, there is no weapon to be enchanted with magical properties to enable the standard 50% chance of damage incorporeal creatures or to bypass the frequently present yet always ignored DR/magic. the ability to bypass these defences is so omnipresent, especially with other similar abilities as spells or supernatural abilities, I doubt most players would even stop to consider that they would even apply to this.
Note to self: I also need to adjust the Death Comes For You command. It, too, is an extraordinary ability that deals damage. It should probably also be a fear effect while I'm at it. Might as well just make it supernatural like several of the other commands, including both the other damage dealers.
Before, I (partially) addressed this with exceptions built into the auras, letting them ignore damage reduction. It was a quick fix, and it wasn't even a complete fix, as I forgot about incorporeal creatures that, conceptually, should be affected, too.
Anyways, this is a long-winded way of saying that, since I'm rebalancing them already and I don't want to make only a couple of the marshal's auras into supernatural abilities, I would like to look at alternative effects for Inspire Pain and Inspire Retribution. Here are some options I'm considering.
Inspire Pain: Enemies suffer a penalty on all skill and ability checks. The first time each round each enemy takes damage, it must make a Fortitude save or be staggered for 1 round.
Motivate Retribution: Whenever an ally is attacked, if the attacker rolls less than or equal to your aura bonus on the d20, it provokes an attack of opportunity from the ally. If the attack already provoked an attack of opportunity from the ally (such as an attack with an unarmed strike), this aura does not cause it to provoke another. (Similar to, but inverted from paladin's Retribution aura, which could also stand to be looked at.)
Motivate Retribution: Allies gain a bonus on attack rolls and on weapon damage rolls. These bonuses only apply while attacking an opponent that attacked that or another ally subject to this aura in the past 1 round. (Similar to dragon shaman's Fury aura.)