Last month, we looked at the basic rules governing attacks of opportunity. The basics are fine things to talk about, but they seldom cover everything that can come up during play. This time, we'll look at attacks of opportunity in the context of the whole game.
Making an Attack of Opportunity
As noted last month, an attack of opportunity is a melee attack. Unless you have the Combat Reflexes feat (and a Dexterity score of at least 12), you can make only one attack of opportunity each turn. (Some monsters, such as hydras, have the ability to make multiple attacks of opportunity each turn.) You always can opt not to make an attack of opportunity, but if you do, the foe that provoked the attack of opportunity from you completes his action and that particular attack of opportunity is lost to you. (You can't change your mind after you know the result of the foe's action.) Still, you may have a good reason to forego the attack of opportunity. Perhaps later you'll get a chance to make an attack of opportunity against a more dangerous foe.
Even if you're allowed several attacks of opportunity each turn, you make a single melee attack against a foe that provokes an attack of opportunity from you. Should that same foe, however, do something else later during his turn that provokes an attack of opportunity from you, you can make another attack of opportunity if you are able.
When you make an attack of opportunity, you use your full attack bonus (no matter how many other attacks of opportunity you've made during the round). Certain actions you've taken during your previous turn might impose a penalty on your attacks of opportunity, such as using the flurry of blows class feature. If the same foe later provokes another attack of opportunity from you, you can attack that foe again (provided that you're allowed more than one attack of opportunity that round), and you use your full attack bonus for that attack.
You can use any special attack that you can use as a melee attack as an attack of opportunity. That includes disarming, grabbing someone to grapple, sunder, or trip. In the case of a trip attack, you must make the trip attack with whatever weapon you're using to threaten the area where you're making the attack of opportunity.
Though you cannot cast a spell as an attack of opportunity, you can use some spells as attacks of opportunity. If you're holding the charge from a touch spell, you can try to touch a foe as an attack of opportunity. Some spells last long enough to let you to make several melee attacks. Spells such as chill touch and produce flame prove useful for attacks of opportunity if someone provokes an attack of opportunity from you.
You cannot make an attack of opportunity against a foe that you cannot see (unless you have the blindsight special quality), and you cannot make an attack of opportunity when you're flat-footed (unless you have the Combat Reflexes feat).
Attack of Opportunity Results: If you hit, you deal damage just as would for any other melee attack. If you've used the Power Attack feat during your turn, you gain whatever damage bonus the feat gives you (just as you took the penalty the feat gave you on your attack roll).
If the damage kills your target or renders the target unconscious, your attack of opportunity foils the action that triggered the attack. If you've made your attack of opportunity in response to a foe using a spell or spell-like ability, your attack interrupts the spell or spell-like ability. If you slay your target or render the target unconscious, the spell or spell-like ability is disrupted. Even if the target survives the attack, the damage you deal might still disrupt the spell or spell-like ability if the target fails a Concentration check. This is one case when an attack of opportunity happens during the action that triggers it rather than before that action.
If you've made your attack of opportunity in response to a foe entering your space, your attack interrupts your foe's movement. Though you make the attack in response to your foe's attempt to enter your square, you make the attack before the foe actually does so. If you slay your target or render the target unconscious, you prevent the foe from leaving the space it occupied just before it tried to enter yours. If you have a reach of 0, you still can make attack of opportunity against foes entering your space. In that case, you make the attack within your space and if you slay your target or render the target unconscious, the foe goes back to the space it left.
Because you must threaten your foe before you can make an attack of opportunity, it pays to examine what area you can threaten and when you threaten it.
As noted earlier, you threaten all the squares on the battlefield into which you can make an armed melee attack. The diagrams on pages 308-310 in the Dungeon Master's Guide show the areas that Medium and bigger creatures threaten when armed with regular weapons and with reach weapons.
A Small creature threatens the same sized area as a Medium creature.
As shown in Diagram 2, a Tiny or smaller creature threatens the square it occupies but not the squares around it. A Tiny or smaller creature cannot make an attack of opportunity unless a foe actually enters its space, such as when a foe tries to make an overrun or bull rush attack. (This is the only case when entering a space triggers an attack of opportunity.)
If you have a natural weapon or the Improved Unarmed Strike feat, you threaten the area around you so long as you have at least one hand free. A creature with several natural weapons might continue to threaten an area even when its "hands" are occupied. For example, a dragon clutching something in both claws could still threaten the area around it with its bite attack and other natural weapons. Likewise, a monk can attack with just about any part of her body and still threatens an area when she doesn't have her hands free. If you're grappling, however, you don't threaten an area, no matter how many weapons you have.
If you use a reach weapon, you threaten more squares because your natural reach doubles. You do not, however, threaten the squares immediately adjacent to you. The reach diagrams in the Dungeon Master's Guide show your normal reach as a band of dark squares and your extended reach with a reach weapon as a band of lighter squares. When you wield a reach weapon, you no longer threaten the darker squares. Remember that you usually make an attack of opportunity before the action that triggers it, so if you're armed with a reach weapon and a foe steps into a square adjacent to you, that foe's movement triggers an attack of opportunity from you. You make that attack while the foe is still in the square you threaten. If you slay your target or render the target unconscious, you prevent the foe from leaving that space.
Adjacent Squares and Reach Weapons: There are some tricks you can use to threaten those adjacent squares when you're using a reach weapon. If you're a monk, your unarmed attacks continue to threaten the squares adjacent to you. Even if you're not a monk, you can use a smaller weapon to threaten the adjacent squares. You'll have to hold the reach weapon in one hand and wield the smaller weapon in the other hand. Since most reach weapons are two-handed weapons, you're only holding onto the reach weapon, not wielding it, and you don't threaten an area with it. Although the rules don't mention it, letting go of a two-handed weapon with one hand or putting a free hand back on the weapon is a free action for you. Drawing the smaller weapon requires an action, but if you have the Quick Draw feat, it's a free action. Note that you can take a free action only during your turn.
If you want to use this trick, you must draw the smaller weapon while it's still your turn. When you do so, you don't threaten any area with your larger weapon until you wield it in two hands again. To resume using the bigger weapon on your turn, you'll have to drop the smaller weapon (a free action) to free up your hand for the bigger weapon.
Weapons such as the spiked gauntlet or armor spikes are ready for use whenever you have a free hand, and you don't need to drop them to use your hand for something else.
Spellcasting and Threatened Areas: You still threaten the area around you after you cast a spell, provided that you are armed. Sometimes the spell itself can "arm" you, as would happen if you cast a touch spell and hold a charge or cast a spell that allows you make melee attacks, such as shocking grasp or chill touch.
The Quick Draw Feat and Threatened Areas: The Quick Draw feat allows you to draw a weapon as a free action. If you're unarmed, you do not threaten an area, even if you have the Quick Draw feat, because you can take a free action only during your turn.
Concealed Creatures: You don't threaten any creature that has total concealment against you (though you can attack into the concealed creature's space and hope for a hit). The blindsight special quality negates foes' concealment when they're within range. Some special qualities, such as blindsense and scent, can reveal an unseen foe's location but don't negate concealment. Similarly, you can use a Listen or Spot check to locate an unseen creature, but that does not negate concealment, so you cannot make an attack of opportunity against that foe.
Cover: You threaten a creature that has cover against your attacks, but you cannot make an attack of opportunity against such a foe.
Actions that Provoke Attacks of Opportunity
An action's description tells you whether it provokes an attack of opportunity. Table 8-2 in the Player's Handbook summarizes actions available to you in combat and notes which ones provoke attacks of opportunity.
The move and run actions are worth a special note. According to Table 8-2, both these actions provoke attacks of opportunity; however, the basic rule for movement and attacks of opportunity still applies. When you move from one square to another in combat, you provoke an attack of opportunity when you leave a threatened square -- not when you enter a threatened square.
When You're Out of Reach
When no foes threaten you (that is, when you're not in any area that a foe threatens) you can get away with an action that normally provokes an attack of opportunity without actually provoking one. For example, if you have greater reach than your foe, you could try to sunder that foe's weapon or shield or disarm that foe without provoking an attack of opportunity provided that you stand outside the area the foe threatens while doing so.
When an Attack of Opportunity Provokes an Attack of Opportunity
In some cases, you can make an attack of opportunity that provokes an attack of opportunity against you. For example, a foe runs past you, leaving a square you threaten and provoking an attack of opportunity from you. If you choose to disarm your foe, you'll provoke an opportunity from that foe (unless you're out of the foe's reach).
Attack of Opportunity Chains: If both you and your foe have multiple attacks of opportunity, the two of you could set up a whole chain of attacks of opportunity. For example, you try to disarm, provoking an attack of opportunity. Your foe responds by attempting to disarm you, and you respond with another disarm attempt.
When this situation occurs, simply allow both foes to keep going with attacks of opportunity until one of them either runs out of attacks of opportunity or chooses not to make any more. Keep track of all the attacks of opportunity each combatant provokes and makes. Resolve the final attack of opportunity in the chain first, and then work forward along the chain until you've resolved all of them or until one opponent's attack of opportunity foils the other's action.
Let's return to our previous example: Let's say you have three attacks of opportunity available and your foe has two.
You make a disarm attempt when your opponent moves past you (attack of opportunity #1). This provokes an attack of opportunity from your foe.
Your foe decides to disarm you in turn (attack of opportunity #2). This provokes an attack of opportunity from you.
You decide to disarm again (attack of opportunity #3).
Your foe also decides to disarm again (attack of opportunity #4 and your foe's second and last attack of opportunity).
You decide to disarm yet again (attack of opportunity #5 and your third and last attack of opportunity).
Your foe would like to disarm you again, but he's out of attacks of opportunity, so that's the end of the chain.
Resolve attack of opportunity #5 first; if you succeed, your foe no longer threatens you and can't continue, bringing the whole process to an end. If you fail to disarm your foe, move on to attack of opportunity #4; now your foe has a chance to end the process by disarming you. Continue until one of you is disarmed or until all the attacks of opportunity are resolved.
Getting Out of Harm's Way
You can leave a threatened square without provoking an attack of opportunity.
Taking a 5-foot Step: If you leave a threatened square by taking a 5-foot step, your movement doesn't provoke an attack of opportunity from any foe that threatens that square. Remember, however, that you can take a 5-foot step only if you don't perform any other movement during your turn (see page 144 in the Player's Handbook).
The Withdraw Action: You can use the withdraw action (see page 143 in the Player's Handbook) to leave one threatened square without provoking attacks of opportunity (that square doesn't count as a threatened square). You can move up to twice your speed when withdrawing, but you're safe only from attacks of opportunity you'd provoke when leaving your first square. Foes you can't see (or discern through blindsight) can make attacks of opportunity against you even when you leave that first square.
The withdraw action is a full-round action, so you can't take other actions if you withdraw during your turn.
The Tumble Skill: With a DC 15 Tumble check, you can move at half speed without provoking attacks of opportunity for that movement. If you fail the check, you still move, but you provoke attacks of opportunity. If you tumble into a foe's square, you still provoke an attack of opportunity from that foe.
With a DC 25 Tumble check, you can pass right through a foe's space without provoking an attack of opportunity. If you fail the check, you stop before entering the foe's space and you provoke an attack of opportunity from that foe.
You can't use the Tumble skill to stop in any space where you can't normally stop, such as a foe's space.
If you're a whole lot bigger or smaller than your foe, you can move through and even stop in the foe's space (see Player's Handbook page 148); you also can do so if you're size Fine, Diminutive, or Small. Entering a foe's space normally provokes an attack of opportunity from that foe, but if you use the Tumble skill to enter the space, you don't provoke an attack of opportunity from the foe if you make your skill check.
Spring Attack: The Spring Attack feat lets you move through some threatened squares without provoking attacks of opportunity. To get the benefit from this feat, you must move and attack a foe, and you must move at least 5 feet both before and after the attack. When you do so, your movement before and after the attack doesn't provoke any attacks of opportunity from that foe, no matter how many threatened squares you leave. Other foes that threaten the squares you leave still can make attacks of opportunity against you.
Ride-By Attack: The Ride-By Attack feat works much like the Spring Attack feat, except that neither you nor your mount provoke any attacks of opportunity from the foe you attack when you move.
Mobility: The Mobility feat doesn't stop attacks of opportunity against you when you leave threatened squares, but it gives you a +4 dodge bonus to AC when you provoke an attack of opportunity for leaving a threatened square. A dodge bonus, however, doesn't help you when you're denied your Dexterity bonus against an attack, as you would be when moving past a foe you can't see.
Combat Reflexes and Attacks of Opportunity
The Combat Reflexes feat allows you to make one extra attack of opportunity per point of Dexterity bonus you have. You still can make only one attack of opportunity for each opportunity that your foe gives you. For example, if you have Combat Reflexes and a Dexterity score of 15 you can make up the three attacks of opportunity each turn. You could make all three of them against the same foe, provided that the foe does three different things that provoke attacks of opportunity. If your foe is a spellcaster and he casts a spell while you threaten him, you can make only one attack of opportunity in response to that spell (even though you are entitled to three attacks of opportunity this round). If, on the other hand, the spellcaster picks up a dropped item, you could make an attack of opportunity against him. If the character then casts a spell, you could make a second attack of opportunity against him. If one of your allies bull rushes the spellcaster and moves him 5 feet, you could make a third attack of opportunity against him.
Note that moving out of more than one threatened square during a turn counts as only one "opportunity" for the moving creature's foes (see page 138 in the Player's Handbook). If the character in the previous example moved and left three (or more) squares that you threaten and did nothing else that provokes attacks of opportunity from you, you'd get only one attack of opportunity against him.
A Pair of Completely Unofficial Rules
I was talking to Andy Collins, senior RPG designer at Wizards of the Coast, about threatened areas and attacks of opportunity not long ago, and the two of us cooked up two rules we're going to try out in our own games.
Tiny Creatures with Reach Weapons
As noted earlier, using a reach weapon doubles your natural reach. If your natural reach is 0, your reach is still 0 when you wield a reach weapon. As a variant, allow Tiny creatures a reach of 5 feet when they use reach weapons.
Using Reach Weapons up Close
Normally, when you wield a reach weapon, the area you threaten forms a hollow ring. You threaten a band of squares away from you, but not the band of squares right next to you. This is the game's way of representing the weapon's physical limits. If the business end of the weapon is at the end of a pole more than 5 feet from you, it's pretty hard to bring that end to bear against a foe right next to you.
Most reach weapons have fairly sturdy shafts, however, and there's no reason why you couldn't use the shaft to clobber someone. Likewise, there's no reason why you couldn't shorten your grip on the weapon so that the business end doesn't stick out so far. To represent these possibilities, you can allow a character to use a reach weapon to attack foes within his natural reach, but with a -4 penalty on attack and damage rolls. The penalties simulate all the difficulties the character has when employing the weapon in this fashion, such as striking with the shaft or messing up the weapon's usual leverage and balance.
About the Author
Skip Williams keeps busy with freelance projects for several different game companies and was the Sage of Dragon Magazine for 18 years. Skip is a co-designer of the D&D 3rd Edition game and the chief architect of the Monster Manual. When not devising swift and cruel deaths for player characters, Skip putters in his kitchen or garden (rabbits and deer are not Skip's friends) or works on repairing and improving the century-old farmhouse that he shares with his wife, Penny, and a growing menagerie of pets.