Attacks of Opportunity
When ever a character "threatens" another character in melee that character has a chance at an Attack of Opportunity. Characters are considered to threaten all opposing forces that are within melee weapon reach that the character is facing. If a fighter is facing three orcs and only two of them attack him, the fighter gets an Attack of Opportunity (AoO) against the third orc. If there is a fourth orc behind the fighter that does not attack, there is no AoO against that opponent because the fighter is not considered to be threatening him.
Attacks of opportunity occur when a threatened character or creature ignores the enemy next to it or turns its back on a foe. The threatening enemy gets to make an immediate melee attack (or sequence of attacks for monsters with multiple attacks) against the threatened creature. Attacks of opportunity cannot be performed with missile weapons or by magic items or spells. This is a free attack that does not take the place of any actions the threatening creature had already planned. These attacks do count towards fatigue however.
A creature can't make more than one attack of opportunity against a single opponent in the course of a combat round, but if several enemies leave themselves open, the creature can make one free attack against each one.
Surprised characters and monsters cannot make attacks of opportunity during the round in which they are surprised.
There is a limit to the number of attacks of opportunity a single creature may make in one round. Warriors and monsters can make three attacks of opportunity plus one per five levels or Hit Dice. All other characters can make one attack of opportunity plus one per five levels. Thirty kobolds trying to swarm past a fighter in a narrow passage will take losses, but some will still get through. Warriors who are in a Heroic Fray have other bonus attacks as well as the normal Attacks of Opportunity.
| Lvl 1-5 | Lvl 6-10 | Lvl 11-15 | Lvl 16-20 | |
| Warrior/Monster | 4 | 5 | 6 | 7 |
| all others | 2 | 3 | 4 | 5 |
Discussion of Rule
I have ruled further clarifications that you can not take an Attack of Opportunity if:
- you do not have any attacks that round
- ie. if you are tied up, or you are prevented from making an attack for some reason, etc.
- using up all attacks does not prevent you from making an AoO
- you did not threaten the opponent your self
- if you are invisible and they cannot see you so they did not know to attack you does not grant you get an AoO
- any melee attack that involves movement does not grant an AoO
- a blood hawk swoop or a dragon snatch
