The mechanical aspect of play in The Fire Down Below campaign will rest on the twin bases of attributes and skills.

About Attributes and Modifiers

When each hero is created, roll 3d6 seven times and assign six of the resulting scores as desired. (Set aside the remaining three dice for now.) The six attributes are:

• Strength (physical power and leverage)
• Dexterity (reflexes, flexibility, and fine motor control)
• Constitution (hardiness and endurance)
• Intelligence (reasoning and memory)
• Wisdom (intuition and sensibility)
• Charisma (sense of self and force of personality)

Each attribute has an associated saving throw, which is a special check made to decrease or escape the negative consequences of some event. More on this below.

Each attribute also has an associated modifier. This modifier is added to (or subtracted from, as a penalty) all checks using that attribute. The modifier is a -2 penalty for attributes at 3/4/5, -1 for 6/7/8, a +1 bonus at 13/14/15, and a +2 bonus at 16/17/18. Attribute scores of 9/10/11/12 have a modifier of 0, without any bonus or penalty. Anything below a score of 3 gives a -3 penalty, while anything above a score of 18 gives a +3 bonus.

The other major factor affecting checks is the character’s proficiency bonus, which slowly increases as the character gains levels, as follows: At level 1, the bonus is +1; at level 2 and 3, +2; 4/5/6 give +3, 7 through 11 give +4, levels 12 through 17 give +5, and levels 20 and up give +6.

About Checks

When the outcome of an action or event is in doubt, the DM may call for a check. Each active participant in the action rolls a d20, then adds all relevant bonuses (and subtracts all relevant penalties). The participant with the highest result “wins” and imposes their will on the action’s outcome. In cases where all active participants are working to overcome something inanimate or passive, then instead a Difficulty Class (DC) is assigned before any dice are rolled, and the active character overcomes it if their check result is higher than the DC.

In case of a tie, both sides technically “win”! The DM and players should talk the matter over and decide on a result where each participant gets what they want but to a reduced degree, or with some drawback, or at some cost. Conversely, for each multiple of ten by which one check result beats the opposition, that character gets a boost. The DM and players should again talk the matter over and decide what extra benefits are gained.

At times there will be a factor that makes a check especially likely to succeed or fail. The former is known as advantage; when you have advantage on a check, roll two d20s and choose whichever result you prefer. The latter is known as disadvantage; again, roll two d20s, but this time you must choose whichever result is worse. Advantage and disadvantage are absolute values: you may have one, or the other, but neither stacks up in multiples. Having both advantage and disadvantage from different factors cancels out both and leads to a normal roll.

Some checks rely almost entirely on a single attribute, such as using Strength to move a heavy stone out of the way. For these attribute checks, roll d20 and add (or subtract) the relevant attribute modifier. Other checks rely entirely on random happenstance; for these luck checks, simply roll a d20 and see what random fortune decrees.

For saves and skill checks, things are a little more complicated and onion-like: there are layers.

1. For any save or skill where the character has no training or practice whatsoever, even latent talent can’t help them. For these “unfamiliar” saves and skills, roll d20 and apply attribute-modifier penalties only.
2. A little bit of practice allows natural affinities to emerge. For these “familiar” saves and skills, you may add attribute-modifier bonuses to the roll.
3. Sustained practice or organized study gives the character some actual technique. For these “trained” skills and saves, add both the attribute modifier and the proficiency bonus to the roll.
4. Finally, long periods of intense focus may allow a character to master the depths of an art and compensate for their weaknesses. For these “expert” skills and saves, add attribute-modifier bonuses but do not subtract penalties, then add the proficiency bonus, and then add another +2. Zang!

All saves and skills begin as “unfamiliar,” but ascend through the layers of proficiency due to choices made during character creation or advancements gained during play.

About Skills

Skills are divided into four groups of six:

• Athletic skills
  • Climb (scaling vertical objects and surfaces)
  • Parkour (running, jumping, rolling, etc. to bypass obstacles)
  • Sneak (moving carefully to avoid attention; covering one’s tracks)
  • Swim (moving and acting effectively while in a liquid)
  • Tinker (fine motor control and sleight of hand)
  • Wriggle (contortion; passing through narrow spaces and escaping bonds)

• Cerebral skills
  • Create* (craft or repair a known type of object)
  • Emote (performing and persuading; call for a boon in desperation)
  • Inspect (search an area, study an object, analyze a situation)
  • Recall* (use a known language or bit of lore; call for a boon through ritual)
  • Scavenge (find food, water, useful objects, and shelter away from home)
  • Tend (give first aid or long-term medical care)

• Combat skills
  • Spear (use weapons about the length of the body)
  • Club (use weapons about the length of the arm)
  • Dagger (use weapons about the size of your hand)
  • Striking (fight with bare hands, feet, elbows, etc.)
  • Grappling (fight with balance, joint locks, and holds)
  • Evading (duck and dodge, or feint to affect an opponent psychologically)

• Sensory skills
  • Sight (notice visual cues and details, judge size and distance)
  • Sound (notice and identify auditory cues; echolocation)
  • Scent (notice and identify chemical cues)
  • Space (proprioception, touch, depth and direction sense, tremorsense)
  • Social (notice and interpret interpersonal cues; judge intent and state of mind)
  • Sixth (notice supernatural cues; intuit the workings of magical phenomena)

*Create is used with objects that the character has studied. The player should keep a list of known objects on their character sheet. Similarly, Recall is used with languages, rituals, and lore that the character has learned, and these too should be recorded. It is simply not possible to create or repair an object when you don’t know what it’s supposed to be like, speak a language you have never read or heard, or remember a fact you have never heard of!