Skills, Weapon groups, and Armor types all have Proficiencies that you can train in. There are three levels of training that a character may have: Untrained, Proficient, and Expert.
For each of your Proficiencies, your proficiency check modifier for that proficiency is equal to:
- the ability base for that proficiency if you are untrained.
- the ability base plus your training bonus (+2) if you are trained.
- the ability base plus your training bonus (+2) plus your expertise bonus (+1) if you have expertise.
Untrained[]
All characters have a basic capacity to performed actions, due to their ability scores. If you are untrained in a skill, armor type or weapon group, you use your base ability modifier as your check modifier.
Certain weapons, armors, skill actions, and other actions are listed as trained only, or even expert only. If an action is listed as trained only or expert only, you grant advantage while attempting the action if you do not have training. If a weapon or armor is listed as trained only or expert only, you grant advantage while wielding that weapon or wearing that armor.
When you are Untrained, Training always grants you Proficiency.
Proficient[]
Characters may gain training in one or more skills, armor types, or weapon groups.
- When you are Proficient in a skill or weapon group, you gain a +2 Training bonus to your check modifier.
- When you are Proficient in an armor type, you reduce the armor check penalty for all armor of that type by your training bonus.
Certain actions, weapons, and armor have the trained only property.
- An action with the 'trained only' property may only be attempted as a stunt, and suffers a -5 penalty to your check result. While you attempt the stunt, you grant advantage.
- A weapon with the 'trained only' property may not be effectively wielded by a character who is untrained in any of that weapon's weapon groups. A character may attempt to attack with such a weapon, but they may not perform opportunity attacks or gain advantage, and they grant advantage as long as they are wielding the weapon.
- Armor may also have the 'trained only' property. A character wearing armor with this property that they are not proficient in grants advantage as long as they wear the armor, and may not gain advantage.
When you are Proficient in a skill, additional Training grants you Expertise.
Expert[]
Characters who are already Proficient in a skill, armor or weapon group may choose to gain Expertise in that skill or weapon group instead, when a feat or class feature would grant them Training. Expertise grants an additional +1 Expertise bonus to your check value, in addition to your +2 Training bonus.
- When you make a skill check to perform an extended action using a skill you have Expertise in, you may choose to treat your check value for that extended action as if you had rolled a 10, instead of rolling. If there is no risk associated with failure, you may also choose to take ten times the normal amount of time required to perform an extended action to treat your check value for the extended action as if you had rolled a 20, instead of rolling.
- When you make an attack with a skill or weapon group that you have Expertise in, add your Expertise bonus to your damage, and you achieve a critical hit if your attack check exceeds the targeted defense by 10 or more.
- When you are wearing armor that you have Expertise in, you reduce the armor check penalty for that armor by your Expertise bonus.
- When wearing a shield that you have Expertise in, you gain your Expertise bonus to your cover bonus against opportunity attacks, area attacks and ranged attacks, and reduce the shield check penalty for that shield by your Expertise bonus.
Certain actions, weapons, and armor have the expert only property.
- An action with the 'expert only' property may only be attempted as a stunt if you are trained, and suffers a -5 penalty to your check result. While you attempt the stunt, you grant advantage.
- A weapon with the 'expert only' property may not be effectively wielded by a character who does not have Expertise in any of that weapon's weapon groups. A character may attempt to attack with such a weapon as a standard action, but they may not perform opportunity attacks or gain advantage, and they grant advantage as long as they are wielding the weapon.