While many ordinary citizens of the Pact Worlds go their entire lives without seeing combat, adventurers and explorers often stumble into situations where a laser pistol or a chainsword is their best option, or they might find themselves fighting for their lives from the back of a vehicle. Combat and tactical play are common parts of the Starfinder Roleplaying Game.

From high-level descriptions of how tactical combat works in Starfinder and robust breakdowns of tactical actions to in-depth explanations of key tactical concepts and special abilities, this contains everything you need to know about tactical play in Starfinder.

How Combat Works

Combat in Starfinder is cyclical. After initial steps that begin a battle, every character acts in turn through a regular cycle of rounds until the combat ends. Regardless of how it plays out, combat follows this sequence. 

1. Determining Awareness: The GM establishes whether any combatant is surprised when combat breaks out. PCs and NPCs usually attempt Perception checks to determine whether they are aware that a fight has started.
2. Determining Initiative Order: The GM and players roll initiative checks for those characters able to act. In combat, characters will act in order of their initiative check results— also known as their initiative counts—from highest to lowest. This order is called the initiative order.
3. Surprise Round: If some but not all of the characters are surprised, combat begins with a surprise round, during which only characters who aren't surprised can act and their choice of actions is limited (see Surprise below). After the surprise round, if any, the GM and players roll initiative checks for any characters that have not yet done so. The GM inserts these characters into the initiative order based on their initiative counts.
4. First Normal Combat Round: All characters act according to initiative order. The full suite of options is available to the combatants when they act, including moving and attacking.
5. Continuing Combat: After all the characters have had a turn, the next normal combat round begins and characters again act in the initiative order determined for this combat. Step 5 then repeats until the combat ends. If a new character enters combat, she rolls an initiative check to determine her initiative count, and the GM inserts her into the established initiative order.

Beginning and Ending Combat

The GM determines when combat begins, often by telling players to roll initiative checks. As long as there are enemies to fight or threats for which it is important to determine who acts in what order, the characters are considered to be in combat. When the GM has decided there are no imminent, known threats left, the combat ends and initiative no longer dictates when characters can act. When the only creatures remaining on one side are so insignificant that they pose no real threat to characters from the opposing side, such as foes with a CR 4 or more below the average level of the PCs, the GM can decide whether the characters are still in combat. See Significant Enemies for more on how to gauge this.

Initiative

When a combatant enters battle, she rolls an initiative check to determine when she'll act in each combat round relative to the other characters. An initiative check is a d20 roll to which a character adds her Dexterity modifier plus any other modifiers from feats, spells, and other effects. The result of a character's initiative check is referred to as her initiative count. The GM determines a combat's initiative order by organizing the characters' initiative counts in descending order. During combat, characters act in initiative order, from highest initiative count to lowest initiative count; their relative order typically remains the same throughout the combat.

If two or more combatants have the same initiative count, the order in which they act is determined by their total initiative modifiers (the character with the highest modifier acts first). If there is still a tie, the tied characters should each roll a d20, and whoever rolls highest goes first. This final method of determining which character's initiative order is earlier is often referred to as “rolling off.” However, if the GM allows it, characters whose initiative results are a tie might decide among themselves which character acts first based on strategies or other tactical factors.

A character rolls to determine her initiative count only once in each combat. Even if a character can't take actions—for example, if she's is under the effect of a hold person spell or is otherwise paralyzed—the character retains her initiative count for the duration of the encounter. The exception is when a character takes an action that results in her initiative changing (see the Ready an Action and Delay).

Any characters who enter combat after it has already begun roll initiative checks when they first enter combat. The GM then inserts them into the initiative order based on their initiative counts.

Combat Round

Each combat round represents 6 seconds in the game world, and there are 10 rounds in 1 minute of combat. A round normally allows each character involved in a combat situation to act. Each time a character acts in a round's normal order, it's called her turn.

Each combat round's activity begins with the character with the highest initiative count and then proceeds to the remaining characters in order of their initiative. When a character's turn comes up in the initiative order, that character performs his entire round's worth of actions. For some exceptions, see Other Actions; for example, delaying can change the order in which you take your turn. Regardless, in a normal combat round on her turn, a character can perform either a full action or a handful of shorter actions (see Actions in Combat for more details about the actions characters can take).

When the rules refer to a “full round,” they usually mean a span of time from a particular initiative count in one round to the same initiative count in the next round. Effects that last a certain number of rounds end just before the same initiative count on which they began. Thus, if a spell with a duration of 1 round is cast on initiative count 14, it ends just before initiative count 14 on the following round.

Surprise

When a combat starts, if a character is not aware of her opponents, she is surprised. The GM determines whether each character is aware by calling for Perception checks or other relevant checks. Surprised combatants take penalties until they have acted in combat.

If some but not all of the combatants are aware of their opponents when combat breaks out, a surprise round takes place before normal combat rounds begin. In order of the characters' initiative results (highest to lowest; see Initiative below), combatants who started the battle aware of their opponents can each take either a standard or move action during the surprise round. Characters can also take swift actions during the surprise round.

If no characters or all characters are aware of their opponents, no surprise round occurs, and combat proceeds as normal.

Surprised Combatants: During combat, combatants who are surprised at the start of battle have the flat-footed condition. As a result, they take a -2 penalty to their Armor Class. Once a character has become aware and acted, she is no longer flat-footed due to being surprised.

Who is Surprised?
A surprise round occurs if some but not all characters involved in a combat are unaware of opponents about to attack. Sometimes all the combatants on a side are aware of their opponents, sometimes none are, and sometimes only a few are. Sometimes several combatants on each side are aware while the rest are surprised. When you can sneak up and catch your enemies by surprise, you enjoy a powerful advantage. It's one way stealthy characters can even the odds when facing foes with superior combat abilities.

Combat Basics

This section presents the key terms and calculations needed to adjudicate the most basic elements of combat: attacking and defending. For a full breakdown of all actions characters can take in combat, see Actions in Combat.

Who Can I Attack?

Combat normally takes place on a battle map with a grid of 1-inch squares, each representing a 5-foot-by-5-foot area, with miniature figures representing characters and monsters. Most player characters and many monsters occupy a single 5-foot square, though some bigger creatures occupy multiple squares. The space a character occupies is usually referred to as her square, though the terms “space” and “square” can be used interchangeably. See Size and Space for more information.

In general, you can fire a ranged weapon at any enemy you can see on the battle map, though this becomes harder the farther away an enemy is. Likewise, you can use a melee weapon to attack an enemy in any square you threaten, which means the squares adjacent to your space, including diagonally, though you may be able to attack creatures farther away if you have reach. See Reach and Threatened Squares for more details.

Attack Roll

An attack roll represents your attempt to hit your opponent in melee or from range on your turn in a round. When you make an attack roll, you roll a d20 and add your attack bonus (see Ranged Attacks and Melee Attacks below, as well as Basic Attack and Damage Bonuses). Various other bonuses can apply from class features, feats, and so on. If your result equals or exceeds the target's Armor Class, you hit and deal damage.

Ranged Attacks

When making a ranged attack, you use a ranged weapon to shoot at an opponent from a distance. If you're attacking with a thrown weapon, your ranged attack bonus equals your base attack bonus (determined by your class and level) + your Strength modifier. Otherwise, your attack bonus for a ranged attack equals your base attack bonus + your Dexterity modifier. When you make a ranged attack, you might also take a penalty for shooting or throwing your weapon beyond the distance listed as its optimal range (see Range and Penalties).

Melee Attacks

When making a melee attack, you use a melee weapon to strike an opponent in hand-to-hand combat. Your attack bonus for a melee attack is equal to your base attack bonus (determined by your class and level) + your Strength modifier.

Basic Attack and Damage Bonuses  
For ease of reference, the following are the basic formulas for calculating ranged attack bonuses, ranged damage, melee attack bonuses, and melee damage. Various other bonuses to attacks and damage can apply from class features, feats, special circumstances, and so on. 

Ranged Attack
Base attack bonus + Dexterity modifier - any range penalty

Ranged Attack with a Thrown Weapon 
Base attack bonus + Strength modifier - any range penalty

Ranged Damage
Weapon damage

Ranged Damage with a Thrown Weapon
Weapon damage + Strength modifier

Melee Attack
Base attack bonus + Strength modifier

Melee Damage
Weapon damage + Strength modifier

Automatic Misses and Hits

A natural 1 (the d20 comes up 1) on an attack roll is always a miss. A natural 20 (the d20 comes up 20) is always a hit. A natural 20 is also a possible critical hit, which could deal more damage (see Critical Hits).

Armor Class (AC)

Your Armor Class (AC) represents how hard it is for opponents to land a solid damaging blow on you. Your Armor Class (AC) is the minimum attack roll result that an opponent needs to hit you and deal damage. Armor Class is divided into two categories: Energy Armor Class (EAC) and Kinetic Armor Class (KAC). Any reference to Armor Class, including bonuses and penalties, applies to both EAC and KAC unless otherwise specified.

Your EAC and KAC are primarily determined by your armor bonus (most often from a suit of armor you wear) plus your Dexterity modifier. Calculate your EAC and KAC using the following formula: 10 + your armor's EAC or KAC armor bonus (whichever is appropriate) + your Dexterity modifier.

Most suits of armor provide separate armor bonuses to EAC and KAC. However, some suits of armor's conditions prevent you from using your full Dexterity bonus. Various other bonuses can apply from class features, feats, special circumstances, and so on. For more information on bonuses.

Energy Armor Class (EAC)

Your Energy Armor Class (EAC) represents the defenses you have against attacks that only deal damage as a result of some kind of energy (such as acid, cold, electricity, fire, or sonic damage). When an opponent's attack would deal only energy damage (if he is using, for example, a laser pistol), his attack roll result is compared to your EAC to determine whether he hits you. Some weapons and effects that use magical or exotic untyped energies might also target your EAC; the description of the weapon or effect tells you if this is the case.

Kinetic Armor Class (KAC)

Your Kinetic Armor Class (KAC) represents the defenses you have against attacks that primarily deal damage as a result of a physical impact. This generally includes attacks that deal bludgeoning, piercing, or slashing damage (described as “kinetic attacks”), attacks that don’t otherwise specify which AC they target, impacts from falling, and damage from crushing or constriction. When a foe's attack would deal such damage (if he is using, for example, a starknife), even if it also deals energy damage, his attack roll result is compared to your KAC to determine whether he hits.

Damage

If your attack hits, you deal damage. Damage first reduces a target's current Stamina Points and then the target's Hit Points (see Injury and Death for more information). In most cases, the type of weapon used determines the amount of damage you deal, though specialization in groups of similar weapons (see the Weapon Specialization feat) and other abilities can increase that amount. Some weapons and abilities may add further effects in addition to dealing damage.

Strength Modifier

When you hit with a melee or thrown ranged weapon, add your Strength modifier to your damage roll's result. However, do not add your Strength modifier to the damage of your grenades and nonthrown ranged attacks.

Multiplying Damage

Sometimes you multiply your damage by some factor, such as on a critical hit. In this case, you do not literally multiply your damage roll result by that factor. Instead, you roll the damage (adding all modifiers) the number of times specified and total the results. If you multiply damage more than once, each multiplier applies to the original, unmultiplied damage. Thus, doubling damage twice is equivalent to rolling the damage (adding all modifiers) three times—once for the original damage and once for each doubling.

Minimum Damage

If penalties reduce a damage result to less than 1, a hit still deals 1 nonlethal damage (see Nonlethal Damage).

Ability Damage

Certain creatures and magical effects can cause temporary or permanent ability damage, which lowers a particular ability score and can reduce its modifier, therefore affecting a range of statistics and rolls. See Ability Damage, Ability Drain, and Negative Levels for more information.

Stamina Points and Hit Points

Whenever you take damage, it first reduces your Stamina Points (SP). Any damage you take beyond your Stamina Points reduces your Hit Points (HP). When your Hit Point total reaches 0, you fall unconscious and are dying, and you lose 1 Resolve Point (RP) each round unless you are stabilized. When your Resolve Points reach 0 but you would lose additional Resolve Points from dying or for any other reason, you're dead. For example, if you have 6 Stamina Points and take 9 damage, your Stamina Points are reduced to 0, you lose 3 Hit Points, and all subsequent damage reduces your HP until you regain Stamina Points. See Injury and Death for more information.

Saving Throws

When you are subject to an unusual effect, such as those imposed by some special weapons and magical attacks, in most cases you can attempt a saving throw (often simply called a “save”) to avoid or reduce the effect. When you attempt a saving throw, you roll a d20 and add your base saving throw bonus (determined by your class and level) and an associated ability score modifier (see below). You might also have other abilities, feats, or items that further modify your saving throws. If your result equals or exceeds the saving throw Difficulty Class (see below), your saving throw is successful.

Saving Throw Types

The three kinds of saving throws are Fortitude, Reflex, and Will.

Fortitude

Fortitude saving throws measure your ability to stand up to physical punishment or attacks against your vitality and health. Apply your Constitution modifier to your Fortitude saving throws.

Reflex

Reflex saving throws test your ability to dodge area attacks and unexpected situations. Apply your Dexterity modifier to your Reflex saving throws.

Will

Will saving throws reflect your resistance to mental influence as well as many magical effects. Apply your Wisdom modifier to your Will saving throws.

Saving Throws in Play

This subsection explains how to determine the difficulty of a saving throw, the result of a successful saving throw, and other key elements in play.

Difficulty Class (DC)

A saving throw against an effect has a Difficulty Class (DC) determined by the effect. For most class features, the DC of an effect you create equals 10 + half your class level + your key ability score modifier. For spells, this is 10 + the level of the spell + your key ability score modifier. See Weapons to find the DC for weapon special properties and critical hit effects. The description of an effect from an item normally lists a saving throw DC.

Automatic Failures and Successes

A natural 1 (the d20 comes up 1) on a saving throw is always a failure. A natural 20 (the d20 comes up 20) is always a success.

Forgoing a Saving Throw

You can voluntarily forgo a saving throw and willingly accept the result of an effect or spell. If you have special resistance to magic, you can suppress that resistance to accept the result (though doing so takes a standard action).

Success

If you succeed at a saving throw against an effect that has no obvious physical indications, you feel a hostile force or a warning tingle but cannot deduce the exact nature of the attack. Likewise, if a creature specifically targeted by one of your effects succeeds at its saving throw, you can generally tell that the creature has succeeded. You do not sense when creatures succeed at saves against effects you create that don't target a single creature.

Saving Throw Terminology

When a spell, an item, or another effect notes that it allows a saving throw, it typically includes the following terminology to describe the result of a successful saving throw. If it does not allow a saving throw, this entry simply says “none.”

Negates

This means that the effect has no impact if you succeed at your saving throw.

Partial

This means that the effect has a lessened impact if you succeed at your saving throw. Some lesser effect occurs, as defined in the effect's description.

Half or Half Damage

This means the effect deals half the normal amount of damage if you succeed at your saving throw.

Disbelieves

A successful saving throw lets you ignore the effect (this usually applies only to illusion effects).

Object

Effects that deal damage generally affect unattended objects normally but don't damage held or attended objects unless the effect specifies that they do. Effects that do something other than deal damage affect objects only if their descriptions specifically say so (this is common only with spells) or if they note “(object)” in the description of the effect's saving throw. An object's total saving throw bonus for Fortitude, Reflex, and Will saves is equal to the object's item level. An object you're holding or wearing uses your saving throw bonus if it is better than the object's own saving throw bonus. Items with an item level of 0 do not receive saving throws when unattended.

Harmless

Normally only spells note whether they are harmless. Such a spell is usually beneficial, not harmful, but if targeted, you can attempt a saving throw, if you like.

Ability Checks

Sometimes a situation will call for you to attempt an ability check: a Strength check, a Dexterity check, a Constitution check, an Intelligence check, a Wisdom check, or a Charisma check. In this case, simply roll a d20 and add the modifier for that associated ability score. It's possible for an ability score modifier to be negative. In this case, subtract that amount from your d20 roll.

Other Rule Terms

In addition to the basic combat mechanics and statistics detailed above, the following terms and rules are also frequently used in Starfinder, both in and out of combat.

Allies and Enemies

Sometimes an ability targets or requires an enemy or an ally, such as the envoy's watch out improvisation. You count as your own ally unless an ability says otherwise. The GM has the final say on whether someone is an enemy or ally; you can't declare one of your fellow party members to be an enemy or an enemy to be an ally just to trigger a special ability. You can reject benefits that would apply to you as the result of being an ally.

Significant Enemies

The GM can and should declare that an ineffectual foe is not enough of a threat to count as an enemy for effects that grant you a benefit when you do something to an enemy or have an enemy do something to you. For example, the commander ability of the mercenary theme requires you to defeat three distinct groups of significant enemies in a day to recover 1 Resolve Point; the mercenary shouldn’t gain this benefit if all they did was step on three different bugs that had no chance of hurting them. In general, a creature with a CR less than or equal to your character level -4 is not a significant enemy.

Armor Proficiency

Most classes grant proficiency with light armor, and more melee-oriented classes, such as soldiers, grant proficiency with heavy armor. If you are wearing armor with which you are not proficient, you take a -4 penalty to your Armor Class.

Powered Armor

Characters can gain proficiency with powered armor by taking the Powered Armor Proficiency feat or via certain class features. Powered armor imposes more significant drawbacks on wearers who aren't proficient with it than other types of armor. If you are wearing powered armor with which you are not proficient, you take a -4 penalty to Armor Class, you are always flat-footed and off-target, and you move at half speed. If the armor has a special form of movement (such as the flight speed of a flight frame), you cannot use that form of movement.

Multiplying More Than Once

When you are asked to multiply a value or roll more than once, the multipliers (x2, x3, and so on) are not multiplied by one another. Instead, you combine them into a single multiplier, with each extra multiple adding 1 less than its value to the first multiple. For example, if you apply a x 2 multiplier twice, the result is equivalent to multiplying the value by 3 (or rolling the damage three times), not multiplying it by 4.

Rounding

Occasionally the rules might ask you to round a result or value. Unless otherwise stated, always round down. For example, if you are asked to take half of 7, the result would be 3.

Weapon Proficiency

Most classes grant proficiency with basic melee weapons and small arms. Combat-oriented classes, such as solarian and soldier, grant proficiency with more categories of weapons, as noted in each class's Weapon Proficiency section. All characters are proficient with any natural weapons they might have, such as a claw or bite attack. If you use a weapon with which you are not proficient, you take a -4 penalty to attack rolls with that weapon, and the DC for any saving throws against that weapon's special effects likewise takes a -4 penalty.

Weapon Specialization

At 3rd level, all classes grant specialization in groups of weapons, which increases the damage you deal with those weapons. See the Weapon Specialization feat for more details.

Wielding Weapons

When the rules refer to wielding a weapon, it means you are holding a weapon with the correct number of hands and can thus make attacks with it. For example, if you are holding a small arm or one-handed melee weapon in a hand, you are considered to be wielding the weapon. If you are carrying a longarm or two-handed melee weapon in one hand or wearing a holstered or sheathed weapon, you are not wielding that weapon.

Rerolls and Rolling Twice

Some abilities allow you to reroll a failed die roll—usually an attack roll, a saving throw, or a skill check. Unless an ability says otherwise, you must decide to use a reroll as soon as you know the result of your first roll but before the GM tells you the outcome or you declare the use of any other ability. You use your rerolled result only if it is better than your original result.

There are also abilities that allow you to make two rolls for a specific die roll and take the better of the two results. These abilities require you to decide to roll twice prior to the die roll. Some abilities allow you to force a foe to roll twice and take the worse of the two results. These abilities also must be announced prior to a die roll being made.

In most cases, once an ability to either reroll or roll twice (or force a foe to roll twice) has been applied, no other similar ability can be applied to that same specific die roll. There are exceptions, however. If one character forces a foe to roll twice and take the worse result, that enemy can still apply the ability to roll twice and take the better result. The reverse is also possible—countering the advantage of rolling twice by forcing a foe to roll twice with a worse result. In both cases, the two abilities negate one other, resulting in a single die roll being made. That die roll cannot then benefit from an ability that would allow a reroll.