Encounter Reactions (DMG)

Once the encounter is set and the DM is ready to role-play the situation, he needs to know how the NPCs or monsters will react. The creatures should react in the manner the DM thinks is most appropriate to the situation.
If the player characters charge a band of randomly encountered orcs with weapons drawn, the DM can easily say, "They snarl and leap to the defense!" Selection of the reaction based on the situation ensures rational behavior and avoids the illogical results that random die rolls can often give.
However, there are times when the DM doesn't have a clue about what the monsters will do. This is not a disaster—it's not even all that unusual. When this happens, the DM can randomly determine an encounter reaction by rolling for a result on Table 59. To use the table, roll 2d10 and add the numbers on the two dice. Increase or decrease this number by any modifiers in the creature description or the morale modifiers (see Table 50 in Chapter 9: Combat).
Using the column that most closely matches the behavior of the player characters, find the entry listed for modified die roll. The result is a general indication of how the creatures will react. This reaction must be interpreted by the DM to fit the situation.
 Table 59: Encounter Reactions
ModifiedDie Roll	Player Characters are:	Player Characters are:	Player Characters are:	Player Characters are:
ModifiedDie Roll	Friendly 	Indifferent 	Threatening 	Hostile
2 or less 	Friendly 	Friendly 	Friendly 	Flight
3 	Friendly 	Friendly 	Friendly 	Flight
4 	Friendly 	Friendly 	Cautious 	Flight
5 	Friendly 	Friendly 	Cautious 	Flight
6 	Friendly 	Friendly 	Cautious 	Cautious
7 	Friendly 	Indifferent 	Cautious 	Cautious
8 	Indifferent 	Indifferent 	Cautious 	Cautious
9 	Indifferent 	Indifferent 	Cautious 	Threatening
10 	Indifferent 	Indifferent 	Threatening 	Threatening
11 	Indifferent 	Indifferent 	Threatening 	Threatening
12 	Cautious 	Cautious 	Threatening 	Threatening
13 	Cautious 	Cautious 	Threatening 	Hostile
14 	Cautious 	Cautious 	Threatening 	Hostile
15 	Cautious 	Threatening 	Threatening 	Hostile
16 	Threatening 	Threatening 	Hostile 	Hostile
17 	Threatening 	Threatening 	Hostile 	Hostile
18 	Threatening 	Threatening 	Hostile 	Hostile
19 	Hostile 	Hostile 	Hostile 	Hostile
20 	Hostile 	Hostile 	Hostile 	Hostile
Within these broad guidelines, a large number of specific reactions are possible.
: Flight: Avoidance, panic, terror, or surrender.
: Friendly: Kind, helpful, conciliatory, or simply non-aggressive.
: Indifferent: Neutral, bored, businesslike, unconcerned, unimpressed, or simply oblivious.
: Cautious: Suspicious, wary, dubious, paranoid, guarded, untrusting, or mildly conciliatory.
: Threatening: Boastful, bravado, blustering, intimidating, short-tempered, or bluffing.
: Hostile: Irritable, hot-tempered, aggressive, or violent.
Of course, a DM should never use a reaction he can't justify. If the DM can't see any reason for an evil efreeti to surrender to the charging player characters, it shouldn't. The table is meant to be an aid to the DM, not an absolute decision-maker.