For every three orcs encountered, there will be a leader and three assistants. These orcs will have 8 hit points each, being the meanest and strongest in the group. If 150 orcs or more are encountered there will be the following additional figures with the band: a subchief and 3-18 guards, each with Armor Class 4, 11 hit points, and +1 damage due to Strength on all attacks. They fight as monsters of 2 Hit Dice (THAC0 19). For every 100 orcs encountered, there will be either a shaman (maximum 5th level priest) or a witch doctor (maximum 4th-level mage). Shamans and witch doctors gain an extra 1d4 hit points for each level above 1st and fight as a monster of 1 Hit Die for every two levels (round fractions up) of spell-casting ability (e.g., a 5th-level shaman has d8+4d4 hit points and fights as a 3 Hit Dice monster.)
If the orcs are not in their lair, there is a 20% chance they will be escorting a train of 1-6 carts and 10-60 slave bearers bringing supplies, loot, or ransom and tribute to their orc chief or a stronger orc tribe. The total value of the goods carried by all of the carts will vary between 10 and 1,000 silver pieces, and each slave bearer will bear goods valued between 5 and 30 silver pieces. If the orcs are escorting a treasure train, double the number of leaders and assistants and add 10 orcs for each cart in the train; one subchief with 5-30 guards will always be in charge.
Orc lairs are underground 75% of the time, in a wilderness village 25% of the time. Orc communities range from small forts with 100-400 orcs to mining communities with 500-2,000 orcs to huge cities (partially underground and partially above ground) with 2,000 to 20,000 orcs. There will always be additional orcs when the encounter is in a creature’s lair: a chief and 5-30 bodyguards (AC 4, 13-16 hit points, attack as monsters with 3 Hit Dice (THAC0 17) and inflict an extra +2 damage on all attacks due to Strength). If the lair is underground, there is a 50% chance that 2-5 ogres per 200 orcs will be living with them. Most lairs above ground are rude villages of wooden huts protected by a ditch, log rampart and log palisade, or more advanced constructions built by other races. The village will have 1-4 watch towers and a single gate. There will be one ballista and one catapult for every 100 adult male orcs.