A very basic restructuring that allows for more intuitive gameplay will be implemented. The idea is to ensure that the system becomes more easily expandable by ensuring that the core system itself is consistent. On the surface level, the rules will function as they always have in almost all cases. The real difference has to do with cooperation in actions, more frequent use of passive skills, and more intuitive reaction interfaces.
When a player declares an action – which includes a desired outcome and an approach anticipated to bring about that action – the GM determines the outcome and describes the result. First, the GM determines whether there is a chance that the action might succeed and a chance that the action might fail. If the GM determines the action can’t succeed, the action is a failure, though the GM may warn the player of the impossibility of the action instead. If the GM determines the action can’t fail, the action is a success. If the GM determines that the action can fail, but there is no risk or cost for failure such that the player can keep trying until they succeed, the action is a success. Otherwise, the GM uses the Core Mechanic to determine the outcome.
Under the Core Mechanic, based on the approach the player is using, the GM determines which Ability (Strength, Dexterity, Constitution, Intelligence, Wisdom, and Charisma) governs the action. The GM also determines an appropriate Difficulty Class for the action. The GM – possibly with help from the player – determines whether the character has a relevant Proficiency. The GM also determines any circumstantial Modifiers. Modifiers can include a static bonus or penalty or the roll can be made with Advantage or Disadvantage.
Once all of that has been determined, the player rolls 1d20 and adds the relevant Ability Modifier, Bonuses and Penalties, and their Proficiency Bonus (if relevant). If the total equals or exceeds the chosen Difficulty Class, the action succeeds. If not, the action fails. If the roll is made with Advantage, the player rolls 2d20 and uses the highest single die roll. If the roll is made with Disadvantage, the player rolls 2d20 and uses the lowest single die roll.
If an action succeeds, the player either accomplishes their desired outcome or makes progress toward that outcome. If the action fails, the player does not accomplish their desired outcome and may suffer costs or risks associated with the roll. Regardless of the success or failure of the action, the GM may also apply consequences based on the player’s approach. The GM describes the results and applies any necessary consequences. Then play continues.
The Reaction Rule. A GM can use the Reaction Rule whenever a character has a moment to respond to something unexpected. The GM describes what the character is aware of. The player then describes their reaction. The GM then determines if the reaction could avoid or mitigate the unexpected event, whether it can succeed, and whether it can fail. The GM then asks for a Saving Throw or Ability Check based on the action. Any spell that can be cast as a Reaction can be used in this instance.
Example: A player has stepped on a pressure plate that will trigger a trap-door opening underneath the forward rank members of the party, Alice and Bob. The GM tells the party “Alice, as your foot hits the ground, you feel a tile give way and hear an audible click. You’ve triggered a pressure plate. What do you do?” Alice, not knowing what is coming, says “I tumble forwards, trying to roll out of the way.” Bob, also unaware of what is coming, says “I raise my shield and stand my ground, gritting my teeth and trying to absorb whatever is about to hit me.” The GM determines that Alice’s action could conceivably carry her forward away from the pit trap. He asks her to make a Dexterity Saving Throw. Bob’s action, however, won’t do him any good. He plunges into the pit.
Example: Carol is trying to sneak past a patrolling goblin to steal a valuable thing. The goblin is walking ahead of her and she’s creeping silently behind, several feet back. Unbeknownst to Carol, she has failed her stealth check and the goblin is about to turn around because he thought he heard her breathing. “Suddenly, the goblin freezes. He’s about to turn, what do you do?” Carol thinks for a minute. “Is the cave wall irregular enough? Can I hide in the folds and crevices?” The GM says, “You could, but you’ll have Disadvantage since you have to move fast.” Carol thinks and says, “I’ll whip my dagger and try to take out the goblin before he turns.” The GM says “okay, give me a ranged attack roll with Advantage since the goblin is currently unaware of you.
Passive Proficiencies as Knowledge. All Proficiencies (skills, tools, weapons, and armor) are assumed to represent both active uses of those things and relevant background knowledge, lore, information, and awareness. When a player with a Proficiency encounters something in the game, the GM should simply give them any relevant information based on their expertise. The GM is advised to gate information based on skill proficiencies in the flavor text and descriptions of items and monsters. In addition, advanced knowledge may be gated behind specific levels of knowledge. A character’s Passive Skill is equal to 8 + Ability Modifier + Proficiency Bonus. If the character has Advantage on such skill checks, the Passive Skill gains an additional +5. If the character has Disadvantage, the character suffers an additional -5. Any bonus that can be granted to a skill roll, such as from Bardic Inspiration or from a Cleric’s bless spell may also be applied to Passive Skills.
Opposed Rolls. When a character attempts an action that puts it in direct opposition with another character’s skills or proficiencies, the DC for the character’s action is 8 + target’s Ability Modifier + target’s Proficiency Bonus for the relevant skill. If the target has Advantage or Disadvantage on the skill, apply +5 or -5 to the DC. Any bonus that can be granted to the target’s skill roll, such as from Bardic Inspiration or from a Cleric’s bless spell may also be applied to the DC. The notation for this is an Ability (Skill) Check vs. Ability (Skill). E.g.: Roll a Dexterity (Stealth) check vs. the scout’s Wisdom (Perception).
Example: Dave is trying to bluff his way past a guard. Dave would roll a Charisma check and add his Proficiency Bonus for his Deception Skill. The DC would be equal to 8 + the guard’s Wisdom modifier + the guard’s Proficiency Bonus for her Insight Skill.
Working Together. When two or more characters work together to accomplish the same task, the character with the higher modifier leads the effort. The leader makes the appropriate ability check and enjoys a +2 bonus for one or two helpers or a +5 bonus for three or more helpers. Characters can only work together if it is task where such help is feasible and possible. In addition, a character can only help with a task if they would not be incapable of attempting the task on their own (due to a lack of Proficiency for instance).
Group Checks. When several PCs are trying to accomplish something as a group, the GM can call for a group check. First, the GM determines whether the group will succeed if any member succeeds (such as with searching) or if the group will fail if any member fails (such as with stealth). In the first scenario, the character with the highest base Ability Check modifier (Proficiency Bonus + Ability Bonus) rolls the check. In the second scenario, the character with the lowest base Ability Check modifier (Proficiency Bonus + Ability Bonus) rolls the check. Bonuses, penalties, Advantage, and Disadvantage are applied normally to the character rolling the check, but these should only be applied after the GM has determined which player has rolled the check.