Folio 20v of the Pisani-Dossi MS.
Original Source http://en.wikipedia.org/wiki/File:Pisani-Dossi_MS.JPG

Skills are used by the Red Ash World Engine to determine if a player can successfully perform a certain action and the outcome of success or failure. You gain and advance skills by spending skill points on them when your character gains a new level. These points you spend will buy skill levels in a specific skill.

The Red Ash World Engine uses a multi-root, multi-tiered skill tree. This means that there are multiple roots (or base) skills that branch out to sub-skills. The skills are further defined by tiers (or steps) with each step building on the previous one. For example Arcana is the root skill for arcane spell casters and is required for anyone to be able to cast arcane spells. Under Arcana you will find a skill for Air on the next tier. Then Air Walk is on the next tier after Air and Fly is on yet another. The cost at each tier has a built in escalation and with spells it will limit the amount of PAP and MAP that the user can channel every turn. So even though you may get a spell like tempest at lower levels it does not mean you can cast it quickly, let alone control it.

Buying skill levels is done with your skill points. For every skill level you buy in a specific tier requires 2 skill levels in the parent skill (one tier back) all the way to the root. In the Arcana skills described above to get to the skill Fly with just one skill level you would need 2 skill levels in Air Walk, 4 skill levels in Air, and 8 Skill levels in Arcana. You can write it like this:

You can also spend skill points on other air based skills like Lightening without buying more Air or Arcana Levels. You can change the above to something like this:

Most spells are highly flexible. You can increase the base damage, range, area, and more depending on the spells definition.

Read classes to see how skills are restricted or favored by a specific class which in turn will affect the cost of a root skill and all of its sub-skills.

• Base - This is a base value used when just paying the minimum PAP and/or MAP Step - This is the amount of increase a skill user can improve the base by. This does not mean the maximum increase, just the step increment. Most skills that have adjustable parts increase by 1 per increase bought.
• X Levels - This is a bonus per your skill level. In a lot of the melee and ballistic skills you will see the benefit as an increase in the attack, damage and more.
• PAP - The cost paid in PAP (Physical Action Points) to make an increased step over the base.
• MAP - The cost paid in MAP (Mental Action Points) to make an increased step over the base.
• Synergy - Synergy is used to determine a percentage savings of either the PAP or MAP when increasing a skills effect or damage. Use this formula to determine the savings and always round up. (Ability Score/10) = Savings. For example the synergy for Duration is the ability power. So any additional duration bought over the base would permit you to buy a a minor savings in cost.
• User - The character that is using the skill.
• Target - The character the skill is being used against.
• # of Targets - Some skills can target more than one.
• Difficulty - This is the difficulty the user sets over the default if listed.
• Saves - This is the savings roll a target(s) can roll if listed.
• Control - This is a spell control value used on higher tiered skills. When a User releases a spell sometimes they have to roll to control the release or else lose control and suffer something bad.
• Maintenance - An additional cost paid to keep a spell active and is paid on a round by round basis.
• Agility, Coordination, Natural Armor, Strength, etc... A number of skills affect ability scores either good or bad.
• Health Points, MAP, PAP, or other derived abilities. A few skills affect derived abilities like the PAP, MAP and health points.
• Melee
• Area - This is an area the user can affect that is center on them. Measured in units of 1square meter.
• Attack - Your melee attack score modifier.
• Damage - The melee damage score modifier.
• Defense - Your melee defense modifier.
• Penetration - Your melee damage penetration modifier.
• Range
• Area - The area that is affected by the skill at the point of contact of the ranged attack. Measured in units of 1 square meter.
• Attack - Your ranged attack score modifier.
• Damage - Your ranged damage score modifier.
• Defense - Your ranged defense score modifier.
• Penetration - Your ranged damage penetration modifier.
• Distance - This is the distance measured in meters that a ranged attack can travel or a skill can affect a target. Any skill without a distance is considered melee unless otherwise stated in the skills description.
• Deflect - Deflect is a defensive combat maneuver to deflect damage. Skills with this present will allow you to modify your roll.
• Duration - The time the effect(s) of a skill can affect a target measured in rounds of combat, hours, days, etc...