Surprise

Surprise is simply the unexpected, unprepared for. Characters can be surprised just as creatures they encounter can. A surprised party is caught unawares or unprepared for a short period while those unsurprised may act (quickly) without fear of retaliation.

Any group will have a "chance to be surprised" (normally 1-3 on a d10 indicates surprise) and the same "chance to surprise others". (i.e. Normally no modifier to the other creature's roll.)

Noise or light can negate the chance of surprising a monster. Similarly, if the party is aware of a monster, the party cannot be surprised by it unless it is also aware of them.

Surprise Procedure

• Surprise for each group is determined by rolling a d10 or, if special modifiers/circumstances exist, a d%.
• Normally, surprise will exist for the group if a 3 or lower is rolled on the d10.

Special Modifiers to the Surprise roll

• In terms of chance to be surprised, a mixed group will always use the most favorable member’s value.
• In terms of chance to surprise others, a mixed group will always use the least favorable member’s value.
• Any modifier to surprise means rolling a d% for surprise (see below). Most modifiers add or subtract 20%. These can be cumulative.
• Typical modifiers to chance to be surprised are keen senses (smell, sight, hearing, or otherwise).
• Typical modifiers to chance to surprise others are silent movement, invisibility, or being hidden or camouflaged.
• Creatures in the Monster Manual will have surprise listed as "normal" or a % value indicating a chance to be surprised; Otherwise (or additionally) the stat block will indicate a % chance to "Surprise others".

Using a d% for Surprise

Normally, creatures are only surprised on a roll of 30% or lower. However, some creatures have a greater than normal chance of surprise.

When dealing with creatures with a lower chance of being surprised than normal, use the following formula (Where Creature 1 is the surprising creature and Creature 2 is the creature rolling for surprise). This will also handle situations where a creature good at surprising others encounters a creature with a lower than normal chance to be surprised.

(Creature 1’s chance to surprise others) minus (30%) 

plus (Creature 2’s normal chance to be surprised) 

equals (Creature 2’s net chance to be surprised).

For example, an elven rogue (normally 70% to surprise others when alone) is successfully moving silently (adding another 20%) up a corridor toward the mouth of a cave. In the cave is a minotaur which is normally very hard to surprise (normally only surprised 15%). So the minotaur will need to roll a 76 or higher on a d% or it will be surprised ([70+20]-[30]+[15]=75). As for the elf, she will be surprised on a roll of 30 or lower (normal chances). So it's entirely possible that both the elf and the minotaur are surprised. However, even if the elf is surprised, it's more likely the minotaur will be surprised for longer.

If surprise is indicated (due to a result on the roll under the net chance to be surprised), the difference between the surprise roll and the net chance of being surprised is checked against Surprise Table II and the number of surprise segments is known.

Surprise Segments

In the 1st round of combat, surprise conditions exist for a number of segments based upon the surprise dice results. Each segment of surprise has a few special combat rules based on the combat action used by the unsurprised party.

Dexterity Modifiers. Any bonus or penalty for reaction due to Dexterity will have a corresponding effect on the number of surprise segments that exist for that individual only. This means the individual can act during any surprise segments that exist for others but this adjustment will never create surprise conditions. While a dexterous creature may act normally during the surprise segments, these segments are treated normally with respect to them (only) and none of the bonus activities are available to them even if they should target surprised creatures. Those creatures with Dexterity penalties could increase the number of surprise segments that exist (with respect to themselves).

Complete Surprise. A surprise result of over 1 segment of surprise is considered “complete surprise” which may play a role in certain circumstances.

Multiple Groups

More than Two Groups. Normally, encounters will be between two conflicting groups, the PCs and the group (of possibly mixed creatures) encountered by the PCs. A "group" must be aligned together against the PCs to be considered a group. If, for example, the PCs encounter a group of bugbear guards overseeing a group of slaves, it could be appropriate to treat the slaves as a separate group if the DM determines they would act against the bugbears (with any sort of effectiveness) when seeing the PCs.

New Combatants Arriving During an Existing Combat. If a new group arrives during a combat another surprise roll will be required by all sides. In any case, any existing combat actions begun in the previous round will complete as normal and original groups may continue to act against each other normally. However, with respect to the newly arrived group, surprise conditions may exist including the ability to engage in special actions during surprise segments.

Combatants Leaving the Area and Returning. An individual can leave a combat passing beyond sight of those still in combat. Awareness and observation of the individual(s) are still in effect and opponents keep an eye out for those having left the area to return. Thus, within a turn (10 rounds) of a creature leaving the area, the original groups cannot be surprised by the same creature returning along the same path—even if they bring new creatures with them. However, the retreating creature may re-enter the fray from a different direction or entrance, assuming at least one full round has elapsed without the creature in combat, they may then attempt to surprise (they will not be surprised of course)—also assuming light and noise are not a factor.

Combat Actions During Surprise Segments

While the length of time (6 seconds) that passes during a surprise segment does not change, certain actions may be completed without the standard delay due to the ability to focus on offensive action. Thus, while all other actions will take the standard time to complete (speaking, spell casting, item use, or moving), certain attack actions will function at a higher rate during a surprise segment.

In other words, normal combat procedure for the first round of combat is followed (declaration, initiative, and execution of combat actions) with the following exceptions.

Special Activity Allowed for Surprise Segments

Each surprise segment allows a surprising group a set of bonus actions, if attacking a surprised creature. These actions take place at the beginning of the first round (using up segments of that round as would be expected). However, at the end of the surprise segments, all creatures then follow combat sequence normally for the remaining segments of the first round of combat (if any).

• Missile Weapons may be used to attack surprised opponents at the normal fire rate usable per segment (rather than per round). If complete surprise exists and the weapons were at the ready, the DM may grant a bonus attack or attacks each segment depending upon circumstances.
• Melee attacks, against a surprised opponent within melee range, operate similarly (treating each segment as a full round even for multiple attacks including iterative attacks). Surprised creatures cannot take immediate attacks (such as those granted against charge attacks).
• Spells may be cast during surprise segments and, if completed before surprise conditions are over, another spell may be used during the remaining segments during the first round of combat. Spells may affect any opponent, surprised or not. Thus, a magic-user with two segments of surprise can use each segment to cast a magic missile spell and still have 8 segments left in the first round with which to cast a fireball. However, if the magic-user decided to cast the fireball first, the spell would take 3 segments of casting time, using up the surprise segments and one normal segment of the round, so no other spells could be cast during the first round.
• Spell-like or innate abilities operate similarly to spells.
• Item use, magic or otherwise, operate in a manner similar to spells or abilities.

Thus, certain quick activities may be used and the character may still act normally during the rest of the first round as if it were a new round.

Other actions, such as movement, retrieving items, or even parleying use the standard amount of time using up surprise segments and continuing into the first round as normal. It is key to remember that movement rate is normally 1 foot per " of a creature’s move speed or double that if charging.

Charging is possible, but such movement will cost the standard amount of time. Although, if close enough, the charger may be able to move and attack a surprised creature during the surprise segments and thus be within melee range of the opponent for the remaining segments of the first round, able to attack again.

Unsurprised Opponents. Any missile or melee attacks against unsurprised opponents during the surprise segments will operate on the normal time scale for the first round. Because it is not always clear which opponents are surprised and which ones are not, a character could inadvertently give up their chance of surprise attacks by attacking an unsurprised creature.