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.
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.

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 Morale).

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.