Combat

Realism-Simulation vs. Game

Combat rules are simplified somewhat as compared to SRD 3.5, Pathfinder, and 5e. In original AD&D, combat rules were minimal; one could focus more on the unfolding story and less on detailed rules – the details of combat would have to be in one’s imagination, not explicitly defined.

“A few brief words are necessary to insure that the reader has actually obtained a game form which he or she desires. Of the two approaches to hobby games today, one is best defined as the realism-simulation school and the other as the game school.  AD&D is assuredly an adherent of the latter school. It does not stress realism … it does little to attempt to simulate anything either …”
“… more ‘realistic’ combat systems could certainly have been included … but they have no real part in a game for a group of players having an exciting adventure.”

Gary Gygax, AD&D Dungeon Masters Guide, 1979

That said, numerous refinements from later D&D versions are included (e.g., AC calculation, the revision of Combat Tables, treatment of negative hit points, and combat maneuvers that have a strong narrative quality).

Combat Procedures

Combat is cyclical; everybody acts in turn in a regular cycle of rounds. Combat follows this sequence:

1. Determine which characters are aware of their opponents at the start of the battle. If some but not all of the combatants are aware of their opponents, a surprise round happens before regular rounds of combat begin. The combatants who are aware of the opponents can act in the surprise round, so they roll for initiative. In initiative order (highest to lowest), combatants who started the battle aware of their opponents each take one action (either a standard action or a move action) during the surprise round. Combatants who were unaware do not get to act in the surprise round. If no one or everyone starts the battle aware, there is no surprise round.
2. Combatants who have not yet rolled initiative do so. All combatants are now ready to begin their first regular round of combat.
3. Combatants act in initiative order (highest to lowest).
4. When everyone has had a turn, the combatant with the highest initiative acts again, and steps 3 and 4 repeat until combat ends.

COMBAT STATISTICS

This section summarizes the statistics that determine success in combat, and then details how to use

ATTACK ROLL

An attack roll represents your attempt to strike your opponent on your turn in a round. When you make an attack roll, you roll a d20 and add your attack bonus. (Other modifiers may also apply to this roll.) If your result equals or beats the target’s Armor Class, you hit and deal damage.

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 threat—a possible critical hit.

ATTACK BONUS

• Your attack bonus with a melee weapon is: Base attack bonus + Strength modifier
• With a ranged weapon, your attack bonus is: Base attack bonus + Dexterity modifier + range penalty

DAMAGE

When your attack succeeds, you deal damage. The type of weapon used determines the amount of damage you deal. Effects that modify weapon damage apply to unarmed strikes and the natural physical attack forms of creatures. Damage reduces a target’s current hit points.

Minimum Damage: If penalties reduce the damage result to less than 1, a hit still deals 1 point of damage.

Strength Bonus: When you hit with a melee or thrown weapon, including a sling, add your Strength modifier to the damage result. A Strength penalty, but not a bonus, applies on attacks made with a bow that is not a composite bow.

Off-Hand Weapon: When you deal damage with a weapon in your off hand, you add only 1/2 your Strength bonus.

Wielding a Weapon Two-Handed: When you deal damage with a weapon that you are wielding two-handed, you add 1-1/2 times your Strength bonus. However, you don’t get this higher Strength bonus when using a light weapon with two hands.

Multiplying Damage: Sometimes you multiply damage by some factor, such as on a critical hit. Roll the damage (with all modifiers) multiple times and total the results. Note: When you multiply damage more than once, each multiplier works off the original, unmultiplied damage.

Ability Damage: Certain creatures and magical effects can cause temporary ability damage (a reduction to an ability score).

ARMOR CLASS

Your Armor Class (AC) represents how hard it is for opponents to land a solid, damaging blow on you. It’s the attack roll result that an opponent needs to achieve to hit you.

Your AC is equal to the following: 10 + armor bonus + shield bonus + Dexterity modifier + size modifier

Note that armor limits your Dexterity bonus, so if you’re wearing armor, you might not be able to apply your whole Dexterity bonus to your AC. Sometimes you can’t use your Dexterity bonus (if you have one). If you can’t react to a blow, you can’t use your Dexterity bonus to AC. (If you don’t have a Dexterity bonus, nothing happens.)

Other Modifiers: Many other factors modify your AC.

• Enhancement Bonuses: Enhancement effects make your armor better.
• Deflection Bonus: Magical deflection effects ward off attacks and improve your AC.
• Natural Armor: Natural armor improves your AC.
• Dodge Bonuses: Some other AC bonuses represent actively avoiding blows. These bonuses are called dodge bonuses. Any situation that denies you your Dexterity bonus also denies you dodge bonuses. (Wearing armor, however, does not limit these bonuses the way it limits a Dexterity bonus to AC.) Unlike most sorts of bonuses, dodge bonuses stack with each other.

Touch Attacks: Some attacks disregard armor, including shields and natural armor. In these cases, the attacker makes a touch attack roll (either ranged or melee). When you are the target of a touch attack, your AC doesn’t include any armor bonus, shield bonus, or natural armor bonus. All other modifiers, such as your size modifier, Dexterity modifier, and deflection bonus (if any) apply normally.

HIT POINTS

The simple bit: When your hit point total reaches 0, you’re disabled. When it reaches –1, you’re dying. When it gets to –10, you’re dead.

See Injury and Death for details.

SPEED

See Movement in Combat.

SURPRISE

When a combat starts, if you are not aware of your opponents and they are aware of you, you’re surprised.

Determining Awareness

Sometimes all the combatants on a side are aware of their opponents, sometimes none are, and sometimes only some of them are. Sometimes a few combatants on each side are aware and the other combatants on each side are unaware.

Determining awareness may call for Listen checks, Spot checks, or other checks.

The Surprise Round: If some but not all of the combatants are aware of their opponents, a surprise round happens before regular rounds begin. Any combatants aware of the opponents can act in the surprise round, so they roll for initiative. In initiative order (highest to lowest), combatants who started the battle aware of their opponents each take a standard action during the surprise round. You can also take free actions during the surprise round. If no one or everyone is surprised, no surprise round occurs.

Unaware Combatants: Combatants who are unaware at the start of battle don’t get to act in the surprise round.

INITIATIVE

Initiative Checks: At the start of a battle, each combatant makes an initiative check. An initiative check is a Dexterity check. Each character applies his or her Dexterity modifier to the roll. Characters act in order, counting down from highest result to lowest. In every round that follows, the characters act in the same order.

If two or more combatants have the same initiative check result, the combatants who are tied act in order of total initiative modifier (highest first). If there is still a tie, the tied characters should roll again to determine which one of them goes before the other.

Inaction: Even if you can’t take actions, you retain your initiative score for the duration of the encounter.

ATTACKS OF OPPORTUNITY

Sometimes a combatant in a melee lets her guard down. In this case, combatants near her can take advantage of her lapse in defense to attack her for free. These free attacks are called attacks of opportunity.

Threatened Squares: You threaten all squares into which you can make a melee attack, even when it is not your action. Generally, that means everything in all squares adjacent to your space (including diagonally). An enemy that takes certain actions while in a threatened square provokes an attack of opportunity from you. If you’re unarmed, you don’t normally threaten any squares and thus can’t make attacks of opportunity.

Reach Weapons: Most creatures of Medium or smaller size have a reach of only 5 feet. This means that they can make melee attacks only against creatures up to 5 feet (1 square) away. However, Small and Medium creatures wielding reach weapons threaten more squares than a typical creature. In addition, most creatures larger than Medium have a natural reach of 10 feet or more.

Provoking an Attack of Opportunity: Two kinds of actions can provoke attacks of opportunity: moving out of a threatened square and performing an action within a threatened square.

• Moving: Moving out of a threatened square usually provokes an attack of opportunity from the threatening opponent. There are two common methods of avoiding such an attack—the 5-foot-step and the withdraw action (see below).
• Performing a Distracting Act: Some actions, when performed in a threatened square, provoke attacks of opportunity as you divert your attention from the battle. Table: Actions in Combat notes many of the actions that provoke attacks of opportunity.

Remember that even actions that normally provoke attacks of opportunity may have exceptions to this rule.

Making an Attack of Opportunity: An attack of opportunity is a single melee attack, and you can only make one per round. You don’t have to make an attack of opportunity if you don’t want to.

An experienced character gets additional regular melee attacks (by using the full attack action), but at a lower attack bonus. You make your attack of opportunity, however, at your normal attack bonus—even if you’ve already attacked in the round.

An attack of opportunity “interrupts” the normal flow of actions in the round. If an attack of opportunity is provoked, immediately resolve the attack of opportunity, then continue with the next character’s turn (or complete the current turn, if the attack of opportunity was provoked in the midst of a character’s turn).

ACTIONS IN COMBAT

THE COMBAT ROUND

Each round represents 6 seconds in the game world. A round presents an opportunity for each character involved in a combat situation to take an action.

Each round’s activity begins with the character with the highest initiative result and then proceeds, in order, from there. Each round of a combat uses the same initiative order. When a character’s turn comes up in the initiative sequence, that character performs his entire round’s worth of actions.

For almost all purposes, there is no relevance to the end of a round or the beginning of a round. A round can be a segment of game time starting with the first character to act and ending with the last, but it usually means a span of time from 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 that they began on.

ACTION TYPES

An action’s type essentially tells you how long the action takes to perform (within the framework of the 6-second combat round) and how movement is treated. There are four types of actions: standard actions, move actions, full-round actions, and free actions.

In a normal round, you can perform a standard action and a move action, or you can perform a full-round action. You can also perform one or more free actions. You can always take a move action in place of a standard action.

In some situations (such as in a surprise round), you may be limited to taking only a single move action or standard action.

• Standard Action: A standard action allows you to do something, most commonly make an attack or cast a spell. See Table: Actions in Combat for other standard actions.
• Move Action: A move action allows you to move your speed or perform an action that takes a similar amount of time. See Table: Actions in Combat. You can take a move action in place of a standard action. If you move no actual distance in a round (commonly because you have swapped your move for one or more equivalent actions), you can take one 5-foot step either before, during, or after the action.
  • Note that readying a weapon counts as a move action.
• Full-Round Action: A full-round action consumes all your effort during a round. The only movement you can take during a full-round action is a 5-foot step before, during, or after the action. You can also perform free actions (see below).
  • Some full-round actions do not allow you to take a 5-foot step.
  • Some full-round actions can be taken as standard actions, but only in situations when you are limited to performing only a standard action during your round. The descriptions of specific actions, below, detail which actions allow this option.
• Free Action: Free actions consume a very small amount of time and effort. You can perform one or more free actions while taking another action normally. However, there are reasonable limits on what you can really do for free.
• Not an Action: Some activities are so minor that they are not even considered free actions. They literally don’t take any time at all to do and are considered an inherent part of doing something else.
• Restricted Activity: In some situations, you may be unable to take a full round’s worth of actions. In such cases, you are restricted to taking only a single standard action or a single move action (plus free actions as normal). You can’t take a full-round action (though you can start or complete a full-round action by using a standard action; see below).

Table: Standard Actions

Regardless of the action, if you move out of a threatened square, you usually provoke an attack of opportunity. This column indicates whether the action itself, not moving, provokes an attack of opportunity. If you aid someone performing an action that would normally provoke an attack of opportunity, then the act of aiding another provokes an attack of opportunity as well. If the object is being held, carried, or worn by a creature, yes. If not, no.
Action	Attack of Opportunity1
Attack (melee)	No
Attack (unarmed)	Yes
Attack (ranged)	Yes
Activate a magic item other than a potion or oil	No
Aid another	Maybe2
Bull rush	Yes
Cast a spell (1 standard action casting time)	Yes
Concentrate to maintain an active spell	No
Dismiss a spell	No
Draw a hidden weapon	No
Drink a potion or apply an oil	Yes
Escape a grapple	No
Feint	No
Light a torch	Yes
Make a dying friend stable	Yes
Overrun	No
Read a scroll	Yes
Ready (triggers a standard action)	No
Sunder a weapon (attack)	Yes
Sunder an object (attack)	Maybe3
Total defense	No
Turn or rebuke undead	No
Use extraordinary ability	No
Use skill that takes 1 action	Usually
Use spell-like ability	Yes

STANDARD ACTION

Attack

Making an attack is a standard action.

Melee Attacks: With a normal melee weapon, you can strike any opponent within 5 feet. (Opponents within 5 feet are considered adjacent to you.) Some melee weapons have reach, as indicated in their descriptions. With a typical reach weapon, you can strike opponents 10 feet away, but you can’t strike adjacent foes (those within 5 feet).

Unarmed Attacks: Striking for damage with punches, kicks, and head butts is much like attacking with a melee weapon, except for the following:

• Attacks of Opportunity: Attacking unarmed provokes an attack of opportunity from the character you attack, provided she is armed. The attack of opportunity comes before your attack. An unarmed attack does not provoke attacks of opportunity from other foes nor does it provoke an attack of opportunity from an unarmed foe.
• An unarmed character can’t take attacks of opportunity (but see “Armed” Unarmed Attacks, below).
• “Armed” Unarmed Attacks: Sometimes a character’s or creature’s unarmed attack counts as an armed attack. A monk, a spellcaster delivering a touch attack spell, and a creature with natural physical weapons all count as being armed. Note that being armed counts for both offense and defense (the character can make attacks of opportunity)
• Unarmed Strike Damage: An unarmed strike from a Medium character deals 1d3 points of damage (plus your Strength modifier, as normal). A Small character’s unarmed strike deals 1d2 points of damage, while a Large character’s unarmed strike deals 1d4 points of damage. All damage from unarmed strikes is nonlethal damage. Unarmed strikes count as light weapons (for purposes of two-weapon attack penalties and so on).
• Dealing Lethal Damage: You can specify that your unarmed strike will deal lethal damage before you make your attack roll, but you take a –4 penalty on your attack roll. If you have the Improved Unarmed Strike feat, you can deal lethal damage with an unarmed strike without taking a penalty on the attack roll.

Ranged Attacks: With a ranged weapon, you can shoot or throw at any target that is within the weapon’s maximum range and in line of sight. The maximum range for a thrown weapon is five range increments. For projectile weapons, it is ten range increments. Some ranged weapons have shorter maximum ranges, as specified in their descriptions.

Attack Rolls: An attack roll represents your attempts to strike your opponent. Your attack roll is 1d20 + your attack bonus with the weapon you’re using. If the result is at least as high as the target’s AC, you hit and deal damage.

Automatic Misses and Hits: A natural 1 (the d20 comes up 1) on the attack roll is always a miss. A natural 20 (the d20 comes up 20) is always a hit. A natural 20 is also a threat—a possible critical hit.

Damage Rolls: If the attack roll result equals or exceeds the target’s AC, the attack hits and you deal damage. Roll the appropriate damage for your weapon. Damage is deducted from the target’s current hit points.

Multiple Attacks: A character who can make more than one attack per round must use the full attack action (see Full-Round Actions, below) in order to get more than one attack.

Shooting or Throwing into a Melee: If you shoot or throw a ranged weapon at a target engaged in melee with a friendly character, you take a –4 penalty on your attack roll. Two characters are engaged in melee if they are enemies of each other and either threatens the other. (An unconscious or otherwise immobilized character is not considered engaged unless he is actually being attacked.) If your target (or the part of your target you’re aiming at, if it’s a big target) is at least 10 feet away from the nearest friendly character, you can avoid the –4 penalty, even if the creature you’re aiming at is engaged in melee with a friendly character. If you have the Precise Shot feat you don’t take this penalty.

Fighting Defensively as a Standard Action: You can choose to fight defensively when attacking. If you do so, you take a –4 penalty on all attacks in a round to gain a +2 dodge bonus to AC for the same round.

Critical Hits

When you make an attack roll and get a natural 20 (the d20 shows 20), you hit regardless of your target’s Armor Class, and you have scored a threat. The hit might be a critical hit (or “crit”). To find out if it’s a critical hit, you immediately make a critical roll—another attack roll with all the same modifiers as the attack roll you just made. If the critical roll also results in a hit against the target’s AC, your original hit is a critical hit. (The critical roll just needs to hit to give you a crit. It doesn’t need to come up 20 again.) If the critical roll is a miss, then your hit is just a regular hit.

A critical hit means that you roll your damage more than once, with all your usual bonuses, and add the rolls together. Alternatively, roll for damage once and double the result. Unless otherwise specified, the threat range for a critical hit on an attack roll is 20, and the multiplier is x2.

Increased Threat Range: Sometimes your threat range is greater than 20. That is, you can score a threat on a lower number. In such cases, a roll of lower than 20 is not an automatic hit. Any attack roll that doesn’t result in a hit is not a threat.

Increased Critical Multiplier: Some weapons deal better than double damage on a critical hit.

Spells and Critical Hits: A spell that requires an attack roll can score a critical hit. A spell attack that requires no attack roll cannot score a critical hit.

Total Defense

You can defend yourself as a standard action. You get a +4 dodge bonus to your AC for 1 round. Your AC improves at the start of this action. You can’t combine total defense with fighting defensively or with the benefit of the Combat Expertise feat (since both of those require you to declare an attack or full attack). You can’t make attacks of opportunity while using total defense.

MOVE ACTIONS

With the exception of specific movement-related skills, most move actions don’t require a check.

Move

The simplest move action is moving your speed. If you take this kind of move action during your turn, you can’t also take a 5-foot step. Many nonstandard modes of movement are covered under this category, including climbing (up to one-quarter of your speed) and swimming (up to one-quarter of your speed).

• Accelerated Climbing: You can climb one-half your speed as a move action by accepting a –5 penalty on your Climb check.
• Crawling: You can crawl 5 feet as a move action. Crawling incurs attacks of opportunity from any attackers who threaten you at any point of your crawl.

Draw or Sheathe a Weapon

Drawing a weapon so that you can use it in combat, or putting it away so that you have a free hand, requires a move action. This action also applies to weapon-like objects carried in easy reach, such as wands. If your weapon or weapon-like object is stored in a pack or otherwise out of easy reach, treat this action as retrieving a stored item. If you have the Two-Weapon Fighting feat, you can draw two light or one-handed weapons in the time it would normally take you to draw one.

Drawing ammunition for use with a ranged weapon (such as arrows, bolts, sling bullets, or shuriken) is a free action.

Ready or Loose a Shield

Strapping a shield to your arm to gain its shield bonus to your AC, or unstrapping and dropping a shield so you can use your shield hand for another purpose, requires a move action. Dropping a carried (but not worn) shield is a free action.

Manipulate an Item

In most cases, moving or manipulating an item is a move action. This includes retrieving or putting away a stored item, picking up an item, moving a heavy object, and opening a door. Examples of this kind of action, along with whether they incur an attack of opportunity, are given in Table: Actions in Combat.

Direct or Redirect a Spell

Some spells allow you to redirect the effect to new targets or areas after you cast the spell. Redirecting a spell requires a move action and does not provoke attacks of opportunity or require concentration.

Stand Up

Standing up from a prone position requires a move action and provokes attacks of opportunity.

Mount/Dismount a Steed

Mounting or dismounting from a steed requires a move action.
Fast Mount or Dismount: You can mount or dismount as a free action with a DC 20 Ride check (your armor check penalty, if any, applies to this check). If you fail the check, mounting or dismounting is a move action instead. (You can’t attempt a fast mount or fast dismount unless you can perform the mount or dismount as a move action in the current round.)

FULL-ROUND ACTIONS

A full-round action requires an entire round to complete. Thus, it can’t be coupled with a standard or a move action, though if it does not involve moving any distance, you can take a 5-foot step.

Full Attack

If you get more than one attack per round because your base attack bonus is high enough, because you fight with two weapons or a double weapon or for some special reason you must use a full-round action to get your additional attacks. You do not need to specify the targets of your attacks ahead of time. You can see how the earlier attacks turn out before assigning the later ones.

The only movement you can take during a full attack is a 5-foot step. You may take the step before, after, or between your attacks.

If you get multiple attacks because your base attack bonus is high enough, you must make the attacks in order from highest bonus to lowest. If you are using two weapons, you can strike with either weapon first. If you are using a double weapon, you can strike with either part of the weapon first.

Deciding between an Attack or a Full Attack: After your first attack, you can decide to take a move action instead of making your remaining attacks, depending on how the first attack turns out. If you’ve already taken a 5-foot step, you can’t use your move action to move any distance, but you could still use a different kind of move action.

Fighting Defensively as a Full-Round Action: You can choose to fight defensively when taking a full attack action. If you do so, you take a –4 penalty on all attacks in a round to gain a +2 dodge bonus to AC for the same round.

Cleave: The extra attack granted by the Cleave feat or Great Cleave feat can be taken whenever they apply. This is an exception to the normal limit to the number of attacks you can take when not using a full attack action.

TWO-WEAPON FIGHTING

If you wield a second weapon in your off hand, you can get one extra attack per round with that weapon. You suffer a –6 penalty with your regular attack or attacks with your primary hand and a –10 penalty to the attack with your off hand when you fight this way. You can reduce these penalties in two ways:

• If your off-hand weapon is light, the penalties are reduced by 2 each. (An unarmed strike is always considered light.)
• The Two-Weapon Fighting feat lessens the primary hand penalty by 2, and the off-hand penalty by 6.

Table: Two-Weapon Fighting Penalties summarizes the interaction of all these factors.

Table: Two-Weapon Fighting Penalties

Circumstances	Primary Hand	Off Hand
Normal penalties	-6	-10
Off-hand weapon is light	-4	-8
Two-Weapon Fighting Special Ability (feat)	-4	-4
Off-hand weapon is light and Two-Weapon Fighting Special Ability (feat)	-2	-2

Double Weapons: You can use a double weapon to make an extra attack with the off-hand end of the weapon as if you were fighting with two weapons. The penalties apply as if the off-hand end of the weapon were a light weapon.

Thrown Weapons: The same rules apply when you throw a weapon from each hand. Treat a dart or shuriken as a light weapon when used in this manner, and treat a bolas, javelin, net, or sling as a one-handed weapon.

Cast a Spell

A spell that takes 1 round to cast is a full-round action. See Magic and Special Abilities in Combat.

This action is otherwise identical to the cast a spell action described under Standard Actions.

Use Special Ability

Using a special ability is usually a standard action, but some may be full-round actions, as defined by the ability.

See Magic and Special Abilities in Combat.

Run

You can run as a full-round action. (If you do, you do not also get a 5-foot step.) When you run, you can move up to four times your speed in a straight line (or three times your speed if you’re in heavy armor). You lose any Dexterity bonus to AC unless you have the Run feat.

See Movement In Combat for details.

See also Disengaging.

Move 5 Feet through Difficult Terrain

In some situations, your movement may be so hampered that you don’t have sufficient speed even to move 5 feet (a single square). In such a case, you may spend a full-round action to move 5 feet (1 square) in any direction, even diagonally. Even though this looks like a 5-foot step, it’s not, and thus it provokes attacks of opportunity normally.

FREE ACTIONS

Free actions don’t take any time at all, though there may be limits to the number of free actions you can perform in a turn. Free actions rarely incur attacks of opportunity. Some common free actions are described below.

Drop an Item

Dropping an item in your space or into an adjacent square is a free action.

Drop Prone

Dropping to a prone position in your space is a free action.

Speak

In general, speaking is a free action that you can perform even when it isn’t your turn. Speaking more than few sentences is generally beyond the limit of a free action.

Cease Concentration on Spell

You can stop concentrating on an active spell as a free action.

Cast a Quickened Spell

You can cast a quickened spell (see the Quicken Spell feat) or any spell whose casting time is designated as a free action as a free action. Only one such spell can be cast in any round, and such spells don’t count toward your normal limit of one spell per round. Casting a spell with a casting time of a free action doesn’t incur an attack of opportunity.

MISCELLANEOUS ACTIONS

Take 5-Foot Step

You can move 5 feet in any round when you don’t perform any other kind of movement. Taking this 5-foot step never provokes an attack of opportunity. You can’t take more than one 5-foot step in a round, and you can’t take a 5-foot step in the same round when you move any distance.

You can take a 5-foot step before, during, or after your other actions in the round. You can only take a 5-foot-step if your movement isn’t hampered by difficult terrain or darkness. Any creature with a speed of 5 feet or less can’t take a 5-foot step, since moving even 5 feet requires a move action for such a slow creature. You may not take a 5-foot step using a form of movement for which you do not have a listed speed.

See also Magic and Special Abilities in Combat.

BIG AND LITTLE CREATURES IN COMBAT

Creatures smaller than Small or larger than Medium have special rules relating to position.
Tiny, Diminutive, and Fine Creatures: Very small creatures take up less than 1 square of space. This means that more than one such creature can fit into a single square. A Tiny creature typically occupies a space only 2-1/2 feet across, so four can fit into a single square. Twenty-five Diminutive creatures or 100 Fine creatures can fit into a single square. Creatures that take up less than 1 square of space typically have a natural reach of 0 feet, meaning they can’t reach into adjacent squares. They must enter an opponent’s square to attack in melee. This provokes an attack of opportunity from the opponent. You can attack into your own square if you need to, so you can attack such creatures normally. Since they have no natural reach, they do not threaten the squares around them. You can move past them without provoking attacks of opportunity. They also can’t flank an enemy.
Large, Huge, Gargantuan, and Colossal Creatures: Very large creatures take up more than 1 square.
Creatures that take up more than 1 square typically have a natural reach of 10 feet or more, meaning that they can reach targets even if they aren’t in adjacent squares.
Unlike when someone uses a reach weapon, a creature with greater than normal natural reach (more than 5 feet) still threatens squares adjacent to it. A creature with greater than normal natural reach usually gets an attack of opportunity against you if you approach it, because you must enter and move within the range of its reach before you can attack it. (This attack of opportunity is not provoked if you take a 5-foot step.)
Large or larger creatures using reach weapons can strike up to double their natural reach but can’t strike at their natural reach or less.

Table: Creature Size and Scale

Size Category	Size1 Modifier	Grapple2 Modifier	Hide3 Modifier	Height or Length4	Weight5	Space6	Natural Reach6 (Tall)	Natural Reach6 (Long)
A creature’s size modifier is applied to it’s attack bonus and Armor Class. Assumes vs. a Medium character. See the Grapple special attack. See the Hide skill. Biped’s height, quadruped’s body length (nose to base of tail) Assumes that the creature is roughly as dense as a regular animal. A creature made of stone will weigh considerably more. A gaseous creature will weigh much less. These values are typical for creatures of the indicated size. Some exceptions exist.
Fine	+8	-16	+16	6 in. or less	1/8 lb. or less	½ ft.	0 ft.	0 ft.
Diminutive	+4	-12	+12	6 in. – 1 ft.	1/8 lb. – 1 lb.	1 ft.	0 ft.	0 ft.
Tiny	+2	-8	+8	1 ft. – 2 ft.	1 lb. – 8 lb.	2½ ft.	0 ft.	0 ft.
Small	+1	-4	+4	2 ft. – 4 ft.	8 lb. – 60 lb.	5 ft.	5 ft.	5 ft.
Medium	+0	+0	+0	4 ft. – 8 ft.	60 lb. – 500 lb.	5 ft.	5 ft.	5 ft.
Large	-1	+4	-4	8 ft. – 16 ft.	500 lb. – 2 tons	10 ft.	10 ft.	5 ft.
Huge	-2	+8	-8	16 ft. – 32 ft.	2 tons – 16 tons	15 ft.	15 ft.	10 ft.
Gargantuan	-4	+12	-12	32 ft. – 64 ft.	16 tons – 125 tons	20 ft.	20 ft.	15 ft.
Colossal	-8	+16	-16	64 ft. or more	125 tons or more	30 ft.	30 ft.	20 ft.

COMBAT MODIFIERS

FAVORABLE AND UNFAVORABLE CONDITIONS

Table: Attack Roll Modifiers

Attacker is…	Melee	Ranged
An entangled character also takes a -4 penalty to Dexterity, which may affect his attack roll. The defender loses any Dexterity bonus to AC. This bonus doesn’t apply if the target is blinded. Most ranged weapons can’t be used while the attacker is prone, but you can use a crossbow or shuriken while prone at no penalty.
Dazzled	-1	-1
Entangled	-21	-21
Flanking defender	+2	—
Invisible	+22	+22
On higher ground	+1	+0
Prone	-4	—3
Shaken or frightened	-2	-2
Squeezing through a space	-4	-4

Table: Armor Class Modifiers

Defender is…	Melee	Ranged
The defender loses any Dexterity bonus to AC. An entangled character takes a -4 penalty to Dexterity. Roll randomly to see which grappling combatant you strike. That defender loses any Dexterity bonus to AC. Treat the defender’s Dexterity as 0 (-5 modifier). Rogues can sneak attack helpless or pinned defenders.
Behind cover (50%)	+4	+4
Blinded	-21	-21
Concealed or invisible	See Concealment
Cowering	-21	-21
Entangled	+02	+02
Flat-footed (such as surprised, balancing, climbing)	+01	+01
Grappling (but attacker is not)	+01	+01, 3
Helpless (such as paralyzed, sleeping, or bound)	-44	+04
Kneeling or sitting	-2	+2
Pinned	-44	+04
Prone	-4	+4
Squeezing through a space	-4	-4
Stunned	-21	-21

COVER

TARGET HAS ABOUT	ARMOR CLASS BONUS
25% cover	+2
50% cover	+4
75% cover	+7
90% cover	+10

Table per AD&D

To determine whether your target has cover from your ranged attack, choose a corner of your square. If any line from this corner to any corner of the target’s square passes through a square or border that blocks line of effect or provides cover, or through a square occupied by a creature, the target has cover (+4 to AC).

When making a melee attack against an adjacent target, your target has cover if any line from your square to the target’s square goes through a wall (including a low wall). When making a melee attack against a target that isn’t adjacent to you (such as with a reach weapon), use the rules for determining cover from ranged attacks.

Low Obstacles and Cover: A low obstacle (such as a wall no higher than half your height) provides cover, but only to creatures within 30 feet (6 squares) of it. The attacker can ignore the cover if he’s closer to the obstacle than his target.

Cover and Attacks of Opportunity: You can’t execute an attack of opportunity against an opponent with cover relative to you.

Cover and Reflex Saves: Cover grants you a +2 bonus on Reflex saves against attacks that originate or burst out from a point on the other side of the cover from you. Note that spread effects can extend around corners and thus negate this cover bonus.

Cover and Hide Checks: You can use cover to make a Hide check. Without cover, you usually need concealment (see below) to make a Hide check.

Soft Cover: Creatures, even your enemies, can provide you with cover against ranged attacks, giving you a +4 bonus to AC. However, such soft cover provides no bonus on Reflex saves, nor does soft cover allow you to make a Hide check.

Big Creatures and Cover: Any creature with a space larger than 5 feet (1 square) determines cover against melee attacks slightly differently than smaller creatures do. Such a creature can choose any square that it occupies to determine if an opponent has cover against its melee attacks. Similarly, when making a melee attack against such a creature, you can pick any of the squares it occupies to determine if it has cover against you.

Total Cover: If you don’t have line of effect to your target he is considered to have total cover from you. You can’t make an attack against a target that has total cover.

Varying Degrees of Cover: In some cases, cover may provide a greater bonus to AC and Reflex saves. In such situations the normal cover bonuses to AC and Reflex saves can be doubled (to +8 and +4, respectively). A creature with this improved cover effectively gains improved evasion against any attack to which the Reflex save bonus applies. Furthermore, improved cover provides a +10 bonus on Hide checks.

CONCEALMENT

TARGET HAS ABOUT	ARMOR CLASS BONUS
25% cover	+1
50% cover	+2
75% cover	+3
90% cover	+4

Table per AD&D

To determine whether your target has concealment from your ranged attack, choose a corner of your square. If any line from this corner to any corner of the target’s square passes through a square or border that provides concealment, the target has concealment.

Concealment Miss Chance: Concealment gives the subject of a successful attack a 20% chance that the attacker missed because of the concealment. If the attacker hits, the defender must make a miss chance percentile roll to avoid being struck. Multiple concealment conditions do not stack.

Total Concealment:  A successful attack into a square occupied by an enemy with total concealment has a 50% miss chance (instead of the normal 20% miss chance for an opponent with concealment).

FLANKING

When making a melee attack, you get a +2 flanking bonus if your opponent is threatened by a character or creature friendly to you on the opponent’s opposite border or opposite corner.

When in doubt about whether two friendly characters flank an opponent in the middle, trace an imaginary line between the two friendly characters’ centers. If the line passes through opposite borders of the opponent’s space (including corners of those borders), then the opponent is flanked.

Exception: If a flanker takes up more than 1 square, it gets the flanking bonus if any square it occupies counts for flanking.

Only a creature or character that threatens the defender can help an attacker get a flanking bonus.
Creatures with a reach of 0 feet can’t flank an opponent.

HELPLESS DEFENDERS

A helpless opponent is someone who is bound, sleeping, paralyzed, unconscious, or otherwise at your mercy.

Regular Attack: A helpless character takes a –4 penalty to AC against melee attacks, but no penalty to AC against ranged attacks. A helpless defender can’t use any Dexterity bonus to AC. In fact, his Dexterity score is treated as if it were 0 and his Dexterity modifier to AC as if it were –5 (and a rogue can sneak attack him).

Coup de Grace: As a full-round action, you can use a melee weapon to deliver a coup de grace to a helpless opponent. You can also use a bow or crossbow, provided you are adjacent to the target. You automatically hit and score a critical hit. If the defender survives the damage, he must make a Fortitude save (DC 10 + damage dealt) or die. A rogue also gets her extra sneak attack damage against a helpless opponent when delivering a coup de grace.

Delivering a coup de grace provokes attacks of opportunity from threatening opponents.

You can’t deliver a coup de grace against a creature that is immune to critical hits. You can deliver a coup de grace against a creature with total concealment, but doing this requires two consecutive full-round actions (one to “find” the creature once you’ve determined what square it’s in, and one to deliver the coup de grace).