Surprise

Surprise

Surprise in combat is not as simple a thing as "they know you're coming, but you don't know they are there". It is assumed that heroes wandering through unknown and dangerous lands are being at least somewhat vigilant, and maintaining a certain degree of situational awareness at all times. It is only when one side (either the monsters or the players) actually prepares an ambush that the element of surprise results in combat effects — namely, an ambush with a surprise round.

These rules attempt to create a fair way for the GM to set up and execute ambushes. Instead of getting to implement an ambush only after every PC fails a perception check (which is rare, and even worse with larger parties), or running ambushes with no agency for the players to notice it ahead of time, this system attempts to establish rules that maintain the danger of a successful ambush, but eliminate the need to either rely on bad luck among the PCs or play heavy-handed to force them to occur.

Setting Up An Ambush

It is generally a good idea to roll initiative before an ambush check is rolled. However, both the initiative rolls and the ambush check should both be made before any creatures are placed on the battle mat (assuming you are using a battle mat). These rolls can even be performed before the GM reveals the map and environment for the encounter, if the GM prefers.

Setting up an ambush, whether you are the GM running a group of monsters, or the player characters, requires at least 1 minute of preparation. It is also generally best if you know with some certainty that the other group (monsters or PC's) will pass through the area in which you are setting up an ambush. This is best accomplished by setting up where the environment naturally converges into a choke point, or playing upon the routines of the other party.

Assuming the ambushing party has sufficient time to prepare, one member of that party rolls a d20. On a result of 10 or greater, the ambush preparations are good enough to cause a surprise round to occur. A roll of 9 or less means that some aspect of the preparations were inadequate to disguise the ambush from casual view, and the approaching targets will see through the attempt without a need for perception checks. In such a case, the encounter is resolved like a normal encounter, with no ambush and no surprise round.

Why can't we all just run around a corner and hide?

It is easy to think that, by running around a corner, and having all members of the group enter a Stealth stance, or hide behind cover, you might be able to surprise enemy creatures who are following you, or are approaching the area. However, such creatures would be aware not only that the hiding creatures must be nearby, but would be on their guard against the rather obvious ambush to follow. As a result, no ambushes or surprise rounds are possible.

However, attacking a creature from stealth does cause the target to be flat-footed against your attack. That's not nothing.

Modifiers to the Ambush Check

• More Prep Time: For each additional minute of preparation, the ambushing party gains a +1 circumstance bonus to the d20 check, to a maximum of +4, if you have 5 or more full minutes to prepare.
• Skilled Ambushers: Some monsters and character classes are better at preparing ambushes, and receive a bonus to the check. This bonus is usually only +1, but can sometimes be higher. Refer to the specific monster entries or character classes for details.

• Some creatures are also capable of setting up an ambush in less than 1 full minute of preparation time, while others are capable of increasing the base DC of a successfully prepared ambush. However, these abilities do not influence the ambush check result.

• Good Hiding Places: If the ambushing area has sufficient hiding places for all creatures such that each creature has total cover from the approaching prey, and all ambushing creatures are remaining as still as possible, and taking no actions other than watching for the approaching victims, they gain a +1 bonus to the check. If any creature has half or more of their body exposed (partial cover), or if any creature is required to squeeze to have cover, this bonus does not apply.
• Invisibility: If all creatures in the ambushing party are invisible, they gain a +1 bonus to the check.

Note that there is no way for the party about to be ambushed to try to penalize this check by spamming Active Perception (Spot) checks. This is primarily because this sort of play is needlessly tedious (rolling a spot check every round, fighting defensively, and then carefully shuffling forward, while tactically sensible, is not heroic and it can really bog down a game for very little gain. If players insist on playing this way, the GM should inflict the fatigued condition on them after a few minutes of this. You can only maintain hyper-vigilance for so long before you either make a mistake, or wear yourself out.).

Ruining the Ambush

If any creature in the ambushing party speaks out loud, or moves from their space, the ambush is ruined and must be set up again, requiring an additional minute of preparation. Successful ambushes require discipline, and can prove quite difficult for highly chaotic creatures.

Triggering the Ambush

If an ambush check is successful, the ambushing party can dictate the starting positions of every creature on the battlefield before the battle begins, within certain limitations:

• No member of the ambushed party may be placed more than 30 feet from any other creature in the ambushed party (i.e. the victims always start at least somewhat together).
• No member of the ambushing party may be placed more than 50 feet from any one member of the ambushed party.
• No more than two ambushing creatures can be placed such that they only threaten any one ambushed creature (i.e. the ambushing party cannot dogpile onto the healer, but they can certainly prioritize them).
• No creature may be placed into any blocked, occupied, or hazardous space, or any space in which they are forced to squeeze, unless there is no other valid space for that creature to begin.

Other than that, placement is wide open. This means the ambushing party has tremendous power over how the battle begins, and can place themselves and their victims into some truly precarious positions.

And, after placement is completed, the combat begins with a special Surprise Round instead of a normal round.

Surprise Round

A surprise round consists of a single standard action for each creature that is aware of the encounter, resolved in initiative order. Any creature that failed to notice the approaching danger loses their standard action during the surprise round. As with any encounter, any creature that has not yet acted during the encounter (including those who cannot act during the surprise round) are Flat-Footed until they take their first action.

Creatures may use this standard action however they wish, though Charge maneuvers are a popular tactic. Note that charge maneuvers always break stealth before the charge attack is resolved. Assuming your target hasn't yet acted, they are still Flat-Footed to the attack, so this is usually no great loss.

Creatures may also use their standard action during a surprise round to take the Total Defense action, even though this normally requires a full-round action.

Surprise rounds count as a special round for purposes of how action points may be used. The round immediately following a surprise round is still considered "round 1". Action points used during the surprise round may use any ability that is normally available in the first round of combat, even though it isn't technically round 1 yet.

Determining Surprise

Each creature in the group being ambushed must roll a Perception check to notice the ambush at the last second. This is a free action that is made against a Challenging DC for the CR (or level) of the ambushing creatures.

All creatures in the group that set up the ambush automatically succeed on the perception check to notice when the surprise round begins. In addition, they are assumed to be making Spot checks each round, once the ambush has been set up. This may allow them to spot any invisible and/or stealthed creatures among their targets prior to the encounter beginning. GMs may wish to make a single such Spot check for all of the creatures in the ambushing group, rather than one per creature, to simplify things, though they may roll for each creature, if they prefer.

Creatures that fail this check are surprised, and lose the standard action normally gained during the surprise round. They remain flat-Footed until they are able to act in the encounter (which will happen at their initiative in the first actual round of combat). Creatures that succeed on the check are not surprised, and may take their standard action during the surprise round, resolved in initiative order.

Note that, just because a creature is aware that an ambush is occurring does not mean that they penetrate any stealth checks, or notice any invisible creatures. They are simply aware that enemy creatures are present. However, in most cases, the ambushing creatures will break their stealth (and/or invisibility) very soon after the ambush is triggered, so it may not be relevant.

In the event that a creature among the group being ambushed succeeds on their Perception check and is higher in the initiative order than all of the ambushing creatures, they are in the peculiar position of not having any targets to attack. Such creatures may take the Total Defense action (as a standard action instead of a full-round action, due to it being a surprise round), ready an action, or hold their action. They may also declare they are Fighting Defensively and also hold or ready an action, gaining the bonus for fighting defensively immediately, though they must remember to apply the penalty for doing so when their action comes up. They may also wish to use their standard action to make an active perception check, to attempt to penetrate any stealth or invisibility among the ambushing creatures. They could then relay any information they learn to their allies. In any case, because they have now acted (even if they ready or hold their action), they are no longer flat-footed against attacks.

Accidental Encounters

It is sometimes possible to surprise creatures when they are so distracted by something else that they stumble into an encounter without the proper awareness that a fight is occurring. This is quite rare, since most monsters and heroes stay pretty aware of their surroundings, and are on the lookout for danger. However, some activities require so much attention that making Passive Perception checks are not possible. If no members of a group are capable of making Passive Perception checks, they are always surprised by an encounter with enemy creatures, even if the enemy creatures made no preparations for an ambush. This means the combat begins with a surprise round, but each side places their own characters (or monsters) normally for the encounter, rather than one side dictating where all creatures begin (as is the case with an ambush).

If even one member of a distracted group is keeping an eye out, and not participating in the distracting action, they can warn their allies prior to any accidental encounters occurring. As a result, such a group would only be surprised if they encounter enemy creatures who have set up a proper ambush.