Anything you do in the game has an effect. Many of these outcomes are easy to adjudicate during the game. If you tell the GM that you draw your sword, no check is needed, and the result is that your character is now holding a sword. Other times, the specific effect requires more detailed rules governing how your choice is resolved. Many spells, magic items, and feats create specific effects, and your character will be subject to effects caused by monsters, hazards, the environment, and other characters.
While a check might determine the overall impact or strength of an effect, a check is not always part of creating an effect. Casting a fly spell on yourself creates an effect that allows you to soar through the air, but casting the spell does not require a check. Conversely, using the Intimidate skill to Demoralize a foe does require a check, and your result on that check determines the effect’s outcome.
The following general rules are used to understand and apply effects.
Most effects are discrete, creating an instantaneous effect when you let the GM know what actions you are going to use. Firing a bow, moving to a new space, or taking something out of your pack all resolve instantly. Other effects instead last for a certain duration. Once the duration has elapsed, the effect ends. The rules generally use the following conventions for durations, though spells have some special durations detailed on pages 304–305.
For an effect that lasts a number of rounds, the remaining duration decreases by 1 at the start of each turn of the creature that created the effect. This is common for beneficial effects that target you or your allies. Detrimental effects often last “until the end of the target’s next turn” or “through” a number of their turns (such as “through the target’s next 3 turns”), which means that the effect’s duration decreases at the end of the creature’s turn, rather than the start.
Instead of lasting a fixed number of rounds, a duration might end only when certain conditions are met (or cease to be true). If so, the effects last until those conditions are met.
Range and Reach
Actions and other abilities that generate an effect typically work within a specified range or a reach. Most spells and abilities list a range—the maximum distance from the creature or object creating the effect in which the effect can occur.
Ranged and thrown weapons have a range increment. Attacks with such weapons work normally up to that range. Attacks against targets beyond that range take a –2 penalty, which worsens by 2 for every additional multiple of that range, to a maximum of a –10 penalty after five additional range increments. Attacks beyond this range are not possible. For example, if you are using a shortbow, your attacks take no penalty against a target up to 60 feet away, a –2 penalty if a target is over 60 and up to 120 feet away, a –4 if a target is over 120 and up to 180 feet away, and so on, up to a maximum distance of 360 feet.
Reach is how far you can physically reach with your body or a weapon. Melee Strikes rely on reach. Your reach also creates an area around your space where other creatures could trigger your reactions. Your reach is typically 5 feet, but weapons with the reach trait can extend this. Larger creatures can have greater reach; for instance, an ogre has a 10-foot reach. Unlike with measuring most distances, 10-foot reach can reach 2 squares diagonally. Reach greater than 10 feet is measured normally; 20-foot reach can reach 3 squares diagonally, 25-foot reach can reach 4, and so on.
Some effects require you to choose specific targets. Targeting can be difficult or impossible if your chosen creature is undetected by you, if the creature doesn’t match restrictions on who you can target, or if some other ability prevents it from being targeted.
Some effects require a target to be willing. Only you can decide whether your PC is willing, and the GM decides whether an NPC is willing. Even if you or your character don’t know what the effect is, such as if your character is unconscious, you still decide if you’re willing.
Some effects target or require an ally, or otherwise refer to an ally. This must be someone on your side, often another PC, but it might be a bystander you are trying to protect. You are not your own ally. If it isn’t clear, the GM decides who counts as an ally or an enemy.
Some effects occupy an area of a specified shape and size. An area effect always has a point of origin and extends out from that point. There are four types of areas: emanations, bursts, cones, and lines. When you’re playing in encounter mode and using a grid, areas are measured in the same way as movement (page 463), but areas’ distances are never reduced or affected by difficult terrain (page 475) or lesser cover (page 476). You can use the diagrams below as common reference templates for areas, rather than measuring squares each time. Many area effects describe only the effects on creatures in the area. The GM determines any effects to the environment and unattended objects.
A burst effect issues forth in all directions from a single corner of a square within the range of the effect, spreading in all directions to a specified radius. For instance, when you cast fireball, it detonates at the corner of a square within 500 feet of you and creates a 20-foot burst, meaning it extends out 20 feet in every direction from the corner of the square you chose, affecting each creature whose space (or even one square of its space) is within the burst.
A cone shoots out from you in a quarter circle on the grid. When you aim a cone, the first square of that cone must share an edge with your space if you’re aiming orthogonally, or it must touch a corner of your space if you’re aiming diagonally. If you’re Large or larger, the first square can run along the edge of any square of your space. You can’t aim a cone so that it overlaps your space. The cone extends out for a number of feet, widening as it goes, as shown in the Areas diagram. For instance, when a green dragon uses its breath weapon, it breathes a cone of poisonous gas that originates at the edge of one square of its space and affects a quarter-circle area 30 feet on each edge.
If you make a cone originate from someone or something else, follow these same rules, with the first square of the cone using an edge or corner of that creature or object’s space instead of your own.
An emanation issues forth from each side of your space, extending out to a specified number of feet in all directions. For instance, the bless spell’s emanation radiates 5 or more feet outward from the caster. Because the sides of a target’s space are used as the starting point for the emanation, an emanation from a Large or larger creature affects a greater overall area than that of a Medium or smaller creature.
A line shoots forth from you in a straight line in a direction of your choosing. The line affects each creature whose space it overlaps. Unless a line effect says otherwise, it is 5 feet wide. For example, the lightning bolt spell’s area is a 60-foot line that’s 5 feet wide.
Line of Effect
When creating an effect, you usually need an unblocked path to the target of a spell, the origin point of an effect’s area, or the place where you create something with a spell or other ability. This is called a line of effect. You have line of effect unless a creature is entirely behind a solid physical barrier. Visibility doesn’t matter for line of effect, nor do portcullises and other barriers that aren’t totally solid. If you’re unsure whether a barrier is solid enough, usually a 1-foot-square gap is enough to maintain a line of effect, though the GM makes the final call.
In an area effect, creatures or targets must have line of effect to the point of origin to be affected. If there’s no line of effect between the origin of the area and the target, the effect doesn’t apply to that target. For example, if there’s a solid wall between the origin of a fireball and a creature that’s within the burst radius, the wall blocks the effect—that creature is unaffected by the fireball and doesn’t need to attempt a save against it. Likewise, any ongoing effects created by an ability with an area cease to affect anyone who moves outside of the line of effect.
Line of Sight
Some effects require you to have line of sight to your target. As long as you can precisely sense the area (as described in Perception on page 464) and it is not blocked by a solid barrier (as described in Cover on pages 476–477), you have line of sight. An area of darkness prevents line of sight if you don’t have darkvision, but portcullises and other obstacles that aren’t totally solid do not. If you’re unsure whether a barrier is solid enough to block line of sight, usually a 1-foot-square gap is enough to maintain line of sight, though the GM makes the final call.