MM 3 General House Rules

Return to Mutants and Masterminds

First off, in my games I have a few guidelines for every PC, to help players avoid building badly imbalanced heroes.

  • The difference between any two PL-balanced numbers should be within PL or less of each other. (For example, at PL10, if your Fortitude is 14, your Will should not be below 4.) With GM permission, this may be raised to a (1.5 x PL) difference at most.
  • As a side effect of the above rule, every defense should be no worse than 1/2 of the campaign PL (rounded down). Going lower requires GM permission; in no case will any defense ever be less than 2.
  • For Active Defenses less than 5, vulnerable imposes -2 and defenseless imposes -5. (Yes, defenseless can push you into the negatives!)

In addition, I recommend the following house rules for every MM3 game . . .

Excellent attack rolls give you "boosts"

When you succeed on an attack ("to hit") roll by two or more degrees, every degree past the first gives you a boost against that opponent. A boost is an abstract combat edge relative to that foe; it may represent achieving a superior position, identifying his weak or blind spot, thinking of a surprising new tactic, etc.

You may spend these boosts after you roll the die to attack that particular foe or to defend against or resist his attacks -- or after he makes a similar roll regarding you and your attacks. For this purpose only, combat maneuvers like Demoralize and Trick count as "attacks."

Spending one boost retroactively adjusts the DC by ±2. Spending three boosts adjusts it by ±5. (You cannot spend two boosts, or more than three boosts, at once.) However, you cannot spend any boosts to improve a natural 1 or reduce the effect of a natural 20.

When the combat ends, all boosts fade.

(This idea, brazenly stolen from Fate, adds a fun tactical feel to combat, while also making "high-skill, low-effect" a more viable combat option -- now they're fairly attractive even compared to perception-range attacks.)

Perception attacks vs. hard-to-see targets

If there's a question of whether you can perceive a target, roll a Perception check. Apply appropriate modifiers for whichever accurate sense you choose to use (usually Vision); e.g., distance, cover, partial concealment, and so on. The DC depends on why the subject is hard to see:

  • If he's moving quickly and/or evasively, the DC is his Dodge + Speed (minimum 5).
  • If he's using Stealth, the DC is his Stealth check result. This only applies if you've been able to watch him throughout the fight! If you've lost track of him, successful use of Stealth means you cannot use your power on him at all.
  • If neither of the above applies, use one of the standard DCs given for Perception skill.

If you fail, but the GM thinks it's still reasonable for you to target the subject, you can -- but the amount you failed by (not the number of degrees!) is added to his resistance roll.

(This is an objective way to determine whether an attacker can "perceive" his target. The optional scaled effect of failure means that it doesn't have to be "all or nothing"; if a defender is hard to see, it may just weaken the attack instead of making it impossible.)

Compelled versus Controlled

These two conditions both involve the subject being subject to orders by an outside force. These orders can be very specific, including which actions to take.

  • Compelled: The subject is struggling for control, which limits him to free actions and one standard action (which may be traded for a move action) each turn. He can be given one order at a time to follow, and must do so completely, but is otherwise free to act. (For example, the controller could order "defend me," "attack your teammate," or "don't defend yourself," but not "attack your teammates while defending me instead of yourself.")
  • Controlled: The subject is completely dominated and has his normal actions. He may be given complex, specific, combined orders. If the controlling force is a PC, the GM may allow the player to temporarily run the subject as an additional character!

The GM may allow the subject an additional resistance roll at a bonus if given an order that goes against deeply held convictions. For example, +2 if ordered to harm a friend or risk the deaths of many or +5 if ordered to harm a loved one or take a potentially suicidal action. (Being ordered to literally commit suicide will break the condition immediately.)

(With Affliction, there's a huge difference between most second-level and third-level conditions, so it's important to emphasize the differences between these two, so that Compelled doesn't become too good.)

Punching Through Barriers

If someone is behind a barrier (inside a vehicle, behind a Force Wall, etc.) but within range of your Damage attack, you may attempt to punch or shoot through it to hit him. The DC is the higher of that needed to hit the barrier or the foe (considering cover, concealment, etc.). If you hit, the foe makes one Toughness roll, using the higher of his personal Toughness or the barrier's Toughness, plus half of the lesser value (rounded down). For simplicity, use this check for effects on both the barrier and the foe.

Example: Zzap is fighting a foe in a helicopter. The helicopter is DC 6 and the foe is DC 14, so he rolls against DC 14 to hit. If successful, the helicopter has Toughness 9 and the foe has Toughness 7, so the effective Toughness is 9 plus half of 7, or 12.

(By a strict reading of the rules, a target behind a Toughness 1 barrier is immune to even a Damage 20 blast. This is a simple rule to get around that without requiring special extras. If you have Breakthrough, Multiattack, or Split, you can attack the barrier and then target separately instead of using this rule.)

Evading Area Attacks

When targeted by any area attack, roll Dodge vs. 10+(effect rank). Add your Defensive Roll level (if any), and add the usual +2 or +5 if you have Evasion. Success means you take half effect; three degrees of success means you avoid the attack completely!

(This is just a slight expansion of the existing evasion rules, allowing an amazing Dodge roll to cancel all damage instead of just half. It also makes Defensive Roll worth the points, since as written it's a horrible deal compared to Protection. The usual exceptions for Perception Area and Perception Range attacks apply, even though I didn't go into them here.)


You may brace yourself as a move action; this must be the last action taken on your turn. You cannot brace if you are currently defenseless or vulnerable, and it cannot be combined with the Defend action (which represents high mobility and the ability to react). This gives you one or two benefits which last until the beginning of your next turn:

  • You add half your Strength (round up, minimum +1) to your Mass rank for the purpose of knockback. (See MM3 Knockdown and Knockback.)
  • Optionally, you become vulnerable but receive a +2 circumstance modifier to your Toughness. (If you have the Withstand Damage advantage, you may choose to instead become defenseless for +5.)

No Variable Skills

Neither the Variable power nor the results of crafting (see MM3 Crafting Rules) can provide enhanced skills. Both combinations have proven to be too abusive, resulting in characters who can literally do anything for a handful of points. Instead, to use Variable or crafting to "improve a skill," enhance its linked ability (and optionally add Jack-of-All-Trades).

Investigation Montages

A montage is used when (1) multiple PCs are trying to beat a hard DC to gather information, (2) the team can justify bringing a wide variety of skills to bear, and (3) it's an important enough scene to justify extra attention and detail. (If everyone is just rolling against the same skill, use the simpler Teamwork rules.)

  • First, the lead player narrates his action and rolls against the master skill. This will usually be Investigation, but different situations can justify a wide variety of skills. If he misses the minimum useful DC by more than 10, don't bother with the montage; the attempt fails. Otherwise, continue.
  • Next, up to five of his teammates can assist, each bringing a different skill or power to bear. The GM can veto anything that he doesn't feel will help; otherwise they roll against DC 15 if it's particularly appropriate or DC 20 if the GM thinks it's a stretch. (For a power, roll against the effect rank or an appropriate attribute; GM's call.) Teamwork adds its usual +5. This is never a routine action unless Skill Mastery is used. The player should narrate how he's helping: using Stealth to sneak up and eavesdrop, using Technology to hack into systems, using Move Object to dangle a stoolie in the air until he talks, and so on.
  • Each success, regardless of the degree, adds +2 to the original master skill result. Failure by one degree costs nothing, but worse failure subtracts (degree - 1) instead.
(An investigation montage allows everyone to be useful, not just the one character with Investigation +20. Despite the name, it can be extended to other checks; e.g., a Persuasion check to improve the team's reputation could benefit from various acts of do-gooding. These rules are from the adventure Church and State by Bradley Robins.)

Extended Negative Measurements Table

-612 oz.3"-116g1/16" (small flea)
-76 oz.1"-123g1/32" (no-see-um)
-83 oz.1/2" (carpenter ant)-131.5g400 μm (pixel)
-91 oz.1/4" (rice grain)-140.6g200 μm (dust mite)
-1015g1/8" (large flea)-150.3g100 μm (hair's width)

(Forgive the switch to metric, but imperial becomes meaningless below a certain size.)

Return to Mutants and Masterminds