Target 10 System for chart-less Attribute Attack Resolution

Mutant Future contains a chart based resolution mechanic for Willpower attacks.  Many mutations call for a Willpower attack rather than a melee or ranged attack roll; the chance of success in a Willpower attack is determined by cross-indexing the attacker's and defender's attribute score on a chart to get a "to hit" number for a d20 roll.

I took this idea and ran with it, coming up with the general idea of attribute attacks.  Any attribute can be the basis of an attribute attack; just like Mutant Future's Willpower attack, there are Intelligence, Dexterity, Constitution, Strength and Charisma attacks.  I used this a lot while writing the "quirks" (mutations by another name) for my Fantasy Quirks character creation supplement for Mutant Future.  I created a version of the Willpower Attack Table found in Mutant Future for any attribute attack:

There are two things that I like about attribute attacks; they do not gain potency while leveling up unless the ability itself increases, so 1st level characters with high attribute scores can contribute meaningfully alongside high level characters in combat; and (more importantly to me) it makes each attribute a defense.  It makes the random attribute increase that is the result of leveling up 80% of the time in the Mutant Future a much more valuable thing.  In a similar fashion to how 3e and 4e took saves and made defenses out of them, this gives me as a DM an easy mechanic to use for all sorts of attacks against the PCs.  Demonic possession?  A Willpower attack with the demons WIL of 15.  A run of the mill pit trap?  Dexterity attack with an attacking DEX of 10.  I would write the previous example using the following shorthand: DEX10 ATT 3d6 (meaning if the Dexterity attack succeeds against the character, the character takes 3d6 damage).

A cloud of gas?  CON15 ATT, 5d6 dmg save for 1/2

Bribing an official?  Obviously a Charisma attack situation.  I don't always (or even most of the time) call for rolls when players attempt to do things, but it is nice to have an easy and unified mechanic to use when I do.  When I don't know the attribute of a creature or situation (in the case of a pit trap or other inanimate attacker or target), I generally use 5/10/15+ as a good guide:  If the creature is not known for that attribute, or if the challenge is easy, I use 5.  If the creature has no reputation for that attribute, good or bad, or if the challenge is moderately difficult I use 10 as the target attribute.  For a creature known for the attribute in question or a difficult challenge, I will use 15 or more.

Today, I looked at the chart a little closer and realized that I could express the attack resolution in very simple terms to allow attribute attacks on the fly without having to look up a target number on a chart.

I realize that many people love looking up numbers on charts.  In my case, it is often one of the only times I have to refer to a book at all while running my Mutant Future game, and I would just as soon not have to break my stride to look at the attribute attack chart one more time.

So here it is:

The “Target 10TM” system for chart-less attribute attack resolution .

(Target 10TM Carl Nash 2010)

d20 roll + (Attackers Attribute - Defenders Attribute) ≥ 10 = Success


In words:  Subtract the defender’s attribute from the attackers attribute.  The result (positive or negative) is the modifier to the d20 roll.  A modified result equal to or greater than 10 is a success.

Example:  

An attacker with CON 13 makes a CON attack on a defender with CON 15.

Attacker’s CON - Defender’s CON = -2

-2 is the modifier to the d20 roll

The attacker would have to roll a 12 or better (12-2=10)