I've come across this situation a few times: do the Brawl and Combat Martial Arts feat chains stack? I've always ruled that no they do not stack with each other, but there always seems to be one person who says: "but brass knuckles make brawl deal lethal damage."

The feats are in the D20 Modern core rulebook.

Brawl: when making an unarmed attack, you recieve a +1 competence bonus on your attack rolls, and you deal nonlethal damage equal to 1d6 + your STR modifier non-lethal damage

Improved brawl: +2 competence bonus, 1d8 + STR modifier non-lethal

Knockout punch: non-lethal strike unarmed is automatically a critical hit

Improved knockout punch: non-lethal unarmed citical hit deals X3 damage

Streetfighting: +1d4 damage once per round with unarmed attack or light melee weapon

Combat martial arts: with an unarmed attack you deal lethal or nonlethal damage[your choice] equal to 1d4 + your STR modifier. your unamred attacks count as armed.

Improved combat martial arts: unamred strike threatens critical hit on 19 or 20

Advanced combat martial arts: unarmed strike critical hit deals X3 damage

Brass Knuckles: when used by a character with the brawl feat, brass knuckles increase the base damage dealt by an unarmed strike by +1 and turn the damage into lethal damage.


3 Answers 3


I remember this question popping up a lot on the forums (And eventually getting an official answer) when I was still playing D20Modern.

The answer is that they do not stack - in any fashion. Not even to the degree DuckTapeal says in his post. Every time you roll to attack somebody, you must decide to either Brawl or use Combat Martial Arts.

The word from the developers on why two fighters couldn't win against each other when only Brawling (For combats where characters have sufficiently high HP and CON values), the answer was that in most brawls, you'd expect a combatant to eventually pick up a bottle or other means of dealing real damage.

SOURCE that brawl and CMA don't stack: https://www.wizards.com/default.asp?x=d20modern/bp/20030320a

SOURCE that Advanced CMA and Knockout Punch don't stack: https://www.wizards.com/default.asp?x=d20modern/bp/20051122a

SOURCE that Street Fighting does stack with CMA: https://www.wizards.com/default.asp?x=d20modern/bp/20060411a

  • \$\begingroup\$ Do you still have a link to that official answer? I understand the reasoning, but there's nothing I can find in the rules to support it, and I'd be interested in seeing what the people who made the game say about it. \$\endgroup\$
    – DuckTapeAl
    Jun 23, 2013 at 18:09
  • \$\begingroup\$ It's been a long while since I last haunted the D20Modern web pages but I can take a look, maybe it's easy to find when you know it's there. EDIT: WHat do you know, that was actually easy to find. \$\endgroup\$
    – shieldfoss
    Jun 23, 2013 at 20:59
  • \$\begingroup\$ Aha. I especially like this line, from the second link: "As an entirely unofficial house rule, I allow the benefits from Brawl and Combat Martial Arts to stack in my own games, and therefore those from Advanced Combat Martial Arts and Improved Knockout Punch would stack as well." \$\endgroup\$
    – DuckTapeAl
    Jun 24, 2013 at 2:16

Brawl and Martial Arts stack with each other.

Each feat chain does a different set of things: Brawl mainly increases hit chances and damage, while Martial Arts mainly provides extra critical power. Nothing in the feat descriptions mentions anything about the chains being incompatible, so they aren't.

If a character had all the feats you list, and had brass knuckles equipped, their unarmed strike would look like this: +2 to attack, 1d8+1+Str mod damage, 19-20/x3 crit

In addition, that character would deal an extra 1d4 damage once per round, and automatically crit flat-footed opponents.

Note: For a character with Advanced Combat Martial Arts, Improved Knockout Punch is redundant. IKP just gives you a x3 crit while using Knockout Punch, while ACMA gives you a x3 crit all the time.


It came up for me recently and I allowed it. I didn't see how the principles of one are in any way violated by the other. You could use streetfighting and Martial Arts together. For example, target a kick to bounce your opponent in to wall behind, or car, or bike rack Etc. That character would deal 1D6(for Brawl) + 2D4 (for MA and StrF) + Str, but I am allowing him to beat zombies to death bare handed. It comes down to your own style and whether or not you feel it unbalances the game for other people, or not.


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