Effects, a Guide

I'm going to use this thread to document all of the effects that are used in the ICRPG ruleset. I've tried to keep the effects as human-readable as possible, but there are some hidden features.

Formatting
Almost all effects use the format "[stat]: [+/-][bonus] [tags]". Many examples of this are given below.
You can place multiple modifiers in a single effect by separating them with a semi-colon. ex. STR: +1; DEX: +1"
You can give the effects readable names by placing text at the beginning of the effect and separating it with a semi-colon. ex. "Magic Armor; ARMOR: +2"

What can be modified
Below is a list of what stats can be modified with effects, along with the shorthand that is used in parenthesis.

Strength (STR)
Dexterity (DEX)
Constitution (CON)
Intelligence (INT)
Wisdom (WIS)
Charisma (CHA)
Basic effort (BASIC)
Weapon effort (WEAPON)
Magic effort (MAGIC)
Ultimate effort (ULTIMATE)
Armor (ARMOR)
Damage reduction (DR)
Damage threshold (DT)
Shield / Damage absorption (SHIELD)
Damage type resistance (RESIST)
Damage type vulnerability (VULN)
Damage type immunity (IMMUNE)
HP Cost for attempts (COST)
Critical hit threshold (CRIT)
All six ability types (STATS)
All effort types (EFFORT)
All ability and effort types (ALL)

Types of modifiers
Below is a list of the types of modifiers that you can use to modify stats

Flat bonus. Works with all STATS, DR, DT, RESIST, VULN, IMMUNE, COST, CRIT, and SHIELD: "STR: +4"
Dice bonus. Works with abilities, effort, COST, RESIST, VULN, IMMUNE (not armor, DR, or DT): "STR: +1d4", or "BASIC: +1d4"
Difficulty modifier. Works only with abilities (not effort, armor, DR, or DT): "STR: EASY" or "CHA: HARD"
A bonus based on another stat. Works with all stats: "DEX: +STR", "WEAPON: +INT", or "ARMOR: +CON"
Unique tags. Different tags are used with different effect types, and are listed below.

You can also apply penalties to rolls using the above rules, such as "STR: -1", "WEAPON: -1d4", or "ARMOR: -INT"

Effort Tags
In addition to modifying with bonuses or dice, effort can also be modified using the following tags:

PIERCING [#]. Effort will ignore or bypass damage reduction / threshold on a target. If a number if specified, then that is how much DR will be ignored, otherwise ALL damage reduction is ignored. ex. "WEAPON: PIERCING 3"
HALF. Effort total will be halved. ex. "MAGIC: HALF"
DOUBLE. Effort total will be doubled. ex. "BASIC: DOUBLE"
MIN. Effort roll is treated as if it rolled the lowest possible result. ex. "EFFORT: MIN"
MAX. Effort roll is treated as if it rolled the highest possible result. ex. "ULTIMATE: MAX"

Damage Reduction
ICRPG uses two different types of damage reduction, neither of which are exposed on player character sheets (they are on NPC sheets though): damage reduction, and a damage threshold. Damage reduction (DR) causes a character to reduce all incoming damage by the amount of DR. Damage threshold (DT) causes a character to ignore all damage below the DT amount. For NPCs, it takes the higher of either the NPC's natural DR/DT, or the amount found in an effect.

Damage Reduction Tags
Damage reduction supports the following tags

HALF. The actor will cut damage taken in half. ex. "DR: HALF"
MIN #. requires a number specified. The actor will take a minimum of the number specified as damage any time effort is applied. ex. "DR: MIN 3" would mean the actor would take a minimum of 3 damage every time they took damage.
MAX #. requires a number specified. The actor will take a maximum of the number specified as damage any time effort is applied. ex. "DR: MAX 1" would mean the actor would take a maximum of 1 damage every time they took damage.

You can further specify which types of effort this applies to by entering the effort type in the effect line, separated by commas. For example:

DR: WEAPON, MAX 1
DR: WEAPON, MAGIC, HALF
DR: MAGIC, HALF
DR: BASIC, WEAPON, MIN 3

Lastly, you can combine all of the above tags into single effect to save on space (no particular order of tags is required):

DR: WEAPON, MAGIC, MIN 2, MAX 4, HALF

Attempt modifiers
In addition to modifying your own stats with an effect, you can apply the following effects to modify how attempts are rolled against a character.

EASYTOHIT. Strength and Dexterity attempts against this character are EASY
HARDTOHIT. Strength and Dexterity attempts against this character are HARD

These effects do not use the normal "STAT: +bonus" format, and instead work by simply putting this text in the effect field (separated by semi-colons if the effect has multiple clauses). For example: "Blur; HARDTOHIT; DEX: EASY"

Damage Type Resistance
This is a type of damage reduction that is separate from effort type (basic, weapon, magic, ultimate). It relies damage types specified with either NPC or PC actions.

RESIST. Reduces damage of a matching type by a flat value, random (dice) value, or by half
VULN. Increases damage of a matching type by a flat value, random (dice) value, or by a factor of 2
IMMUNE. Reduces damage of a matching type to 0.

For all three of these effects, you can specify either a flat number or a dice formula, followed by a list of damage types to affect, separated by commas. Examples:

RESIST: 1d4 fire
RESIST: 1 fire,cold
VULN: 1d4 acid
VULN: blunt
IMMUNE: fire, cold, lightning

Shielding / Damage Absorption
You can use the "SHIELD" effect to grant a temporary hit point buffer that is deducted from before any HP damage is done. Example:

SHIELD: 10

When damage is done to a creature with a SHIELD effect, the damage is deducted from the shield first, before doing any HP damage. Multiple SHIELD effects will stack, and damage will cascade from one to the next until none remain.

Additionally, you can specify types and sources of damage that the SHIELD will absorb (separated by commas). You can also specify "cost" as a damage source, and the shield will only absorb damage taken as a cost to performing an action. Examples

SHIELD: 10 weapon, basic
SHIELD: 10 fire
SHIELD: 10 cost

Critical Hit Threshold
The CRIT effect will modify the critical threshold of attempts. It works in two different ways.

If the CRIT effect is positive then all attempts will treat the specified value as the critical threshold to trigger a critical hit. For example, "CRIT: 18" would set the critical threshold to 18, and thus an 18 on attempt would be a critical success.
If the CRIT effect is a negative number then attempts will subtract that number from 20 to determine the critical threshold. For example, "CRIT: -5" would set the critical threshold at 15.

These two uses can be combined, and they will be handled in the order listed above. If you combined the above examples, the critical threshold will be set to 13 (18 minus 5).
Regen and Degen
These effects apply either healing or damage to the affected character when their turn starts.

REGEN. Regeneration. Heals at the start of turn. "REGEN: 1" or "REGEN: 1d4"
DEGEN. Ongoing damage. Damages at the start of turn. "DEGEN: 1" or "DEGEN: 1d4"

Battle Fury
You can set up battle fury to automatically increment on failed attempts, and expire on successful attempts.

FURY. Battle fury. Adds a bonus to all attempts. Increments its own bonus on a failure, and removes itself automatically on a success. "FURY: +1"

In the game options under "Combat (GM)" are two game settings to control how the fury effect behaves: one to set if battle fury should automatically expire on a success, and the other to set if battle fury to automatically increment on a failed attempt. Both default to yes.

Cost
Players can modify the cost of using actions with the COST effect. It supports both flat numbers and dice (as well as a combination of both)

COST: -2
COST: -1d4

Timers
The actions page of the PC sheet has built in support for effect timers, but you can specify that an effect have a variable duration using the clause: "TIMER: [timer die]" (ex. TIMER: 1d4). If you put the timer clause in an effect, when that effect is applied to a character the timer die is rolled and the effect's duration is set to that amount. As normal, you would separate this clause with semi-colons. ex. Counter Spell cooldown; Timer: 1d4

Extensions
Any extension that modifies the types of effort used will also allow effects to work with the new types. For example, the Quickstart 2e extension replaces the d8 magic effort with GUN effort, and changes magic to a d10 effort. In that case, you could effect the GUN stat in the same way all other effort is modified: GUN: +1, GUN: +1d4, GUN: +DEX, etc.

Updates

April 20th, 2021 - Added cost and crit effects. updated Shield.
April 7th, 2021 - Added damage types, shield
April 6th, 2021 - Added effort and DR tags