Creating Encounter Tables (DMG)

There are a multitude of ways a DM can create encounter tables (as many ways as there are different ranges of die rolls). The choices range from very simple (roll 1d6 for one of six possible choices) to very complicated (roll percentile dice, modify for time of day and weather and cross-index the result with the terrain). With this, and the common characteristics described above, in mind, you can create random encounter tables for virtually any situation.
As already noted, an encounter table can be constructed around virtually any type of die or dice roll. Two of the best, however, are the 2-20 table and the percentile table. Both provide a wide enough range of results to account for the varying frequency of appearance of the monsters the DM wants to use.
==The 2-20 Table==
This table has nineteen openings (although, by doubling up on some entries, more or less than nineteen different encounters can appear on the table). The 2-20 number is generated by adding the roll of 1d8 to that of 1d12. Thus, 2s and 20s are very rare, while there is an equal chance for results from 9 through 13. Monsters are assigned specific positions on the table according to their frequency, as shown on Table 54.
To fill the table, the DM first selects those monsters he wishes to use on the table and counts how many of each type he has. If he has fewer of a given type than the chart provides for, he can repeat entries. If he has more, he either drops some creatures or doubles up some entries.
For example, say the DM is creating an encounter chart for the Desert of Shaar. First he chooses his possible encounters:
Common 	Uncommon
Camel 	Basilisk
Giant centipede	Brass dragon
Herd animal 	Caravan
Ogre 	Hobgoblin
Orc 	Nomads
Huge spider 	Giant scorpion
 	
Rare 	Very rare
Chimera 	Djinni
Pilgrims 	Efreeti
Harpy 	Lamia
Dervishes 	
Salamander 	
The table has six common entries, six uncommon entries, five rare, and three very rare entries. There are also two spots that could be rare or very rare. The DM chooses to arrange his encounters as shown:
DiceRoll	Frequency
2 	Lamia
3 	Djinni
4 	Harpy
5 	Pilgrims
6 	Dervishes
7 	Basilisk
8 	Caravan/Hobgoblins
9 	Huge spider
10 	Ogre
11 	Camel/Herd animal
12 	Giant centipede
13 	Orc
14 	Nomads
15 	Giant scorpion
16 	Dervishes
17 	Chimera
18 	Salamander
19 	Lamia
20 	Djinni
The DM chose not to use the brass dragon or the efreeti, saving these powerful creatures for a special, planned encounter in his adventure. He justifies the presence of the djinni on the table by deciding that it will be helpful to the party, giving them a useful clue about the adventure (unless, of course, they foolishly attack it). To fill the spots of the creatures he set aside, the DM repeated a few entries, meaning they may show up slightly more frequently than might be expected.
==The Percentile Table==
This is another simple form of encounter table. Here, the creature frequency percentages can be used directly. To create a percentile table, the DM repeats the steps given above for selecting and grouping his encounters, again opting not to use the efreeti or the brass dragon. Then the number of creatures at each frequency is divided into the percentage for that frequency (70%, 20%, 7%, and 3%, respectively, for common, uncommon, rare, and very rare). In the earlier example, the list includes six common monsters. (70%), resulting in an 11% spread per monster (66% total). This is repeated for the monsters in each category. The resulting number is the dice range for each creature. Using these values as a guide, he arranges the creatures into a table.
D100Roll 	Creature
Common 	
01-11 	Camel
12-22 	Giant centipede
23-33 	Herd animal
34-44 	Ogre
45-55 	Orc
56-66 	Huge spider
 	
Uncommon 	
67-70 	Basilisk
71-74 	Caravan
75-78 	Hobgoblins
79-82 	Nomads
83-86 	Giant scorpion
 	
Rare 	
87-88 	Chimera
89-90 	Pilgrims
91-92 	Harpy
93-95 	Dervishes
96-97 	Salamander
 	
Very Rare	
98-99 	Lamia
100 	Djinni
Using this method the DM was able to remain reasonably faithful to the frequency percentages for different creatures: 66% as opposed to 70% for common; 20% exactly for uncommon; 11% as opposed to 7% for rare; and 3% for very rare. In creating this table, the DM had to make adjustments here and there to account for all percentage numbers, but doing so allowed him to increase the emphasis on certain monsters.
==Dungeon Encounter Tables==
Dungeon encounter tables are normally set up according to levels—1st, 2nd, 3rd, etc. Each level is a relative measure of the power of those creatures on it. In general, the level of the table corresponds to character level, although characters may also encounter and defeat (or be challenged by) creatures from higher or lower level tables. Generally, when adventuring in a dungeon, characters should meet random encounters that are equal to or no more than two levels higher or lower than their own.
Sometimes dungeons themselves are arranged in levels (although this is by no means required). In this case, the dungeon level and the encounter table correspond. Characters on the 1st-level of the dungeon would encounter creatures from the first level encounter table. This not only keeps the power of the monsters in line with the strength of a typical party, it also maintains the logical structure of the dungeon level. It doesn't make much sense for extremely powerful monsters to mingle freely (and without consequence) among the weaker creatures that inhabit the level.
Determining dungeon level: Figuring the appropriate level for a particular creature is simple. Look up or calculate the experience points of the creature and check this number on Table 55, below. This will tell you where to place the creature.
When constructing the encounter table, creatures with a greater or lesser power than the table being designed can be used. However, each level of difference between creature and table decreases the frequency of appearance by one (a common creature becomes uncommon, a rare creature would be very rare, and so on). Creatures less powerful than the given level seldom venture into such dangerous territory. Creatures more powerful are seldom met to ensure the player characters have a decent chance of survival. After adjustment, these creatures can be added to the table.
In addition, there is a chance that an encountered creature will be more powerful than expected: When designing a 2-20 table, the 20 result could be "Use next highest table"; if a percentile table is used, 98-100 could bump the DM to the next table. Thus, players would never be assured of safety or good odds.
==Wildernesss Encounter Tables==
Unlike the dungeon tables, those used for the wilderness are not so neatly organized according to deadliness or power. One principle of wilderness adventuring (which makes it more dangerous for low-level characters) is that virtually any creature can be met—and often in sizeable numbers. This is a risk the players should be aware of before they take their characters out into the untracked forest.
This does not mean that wilderness adventuring should be impossible for low-level characters. It shouldn't be so deadly that they can't walk three steps before a flight of red dragons appears and turns them to ash with one fiery breath! That's just bad refereeing. Low-level characters should have the opportunity to go on wilderness adventures that they can survive.
Perhaps an area of the nearby forest is regularly patrolled by the King's Wardens who drive off the greater threats to the safety of the population. Lone monsters often escape their notice and sometimes raid the outlying farms. Special encounter tables can be created to reflect the lower levels of monsters that do manage to lurk in these woods, providing low-level characters with a decent but not overpowering challenge.
The greatest consideration in creating wilderness encounter tables is to have a separate table for each type of terrain. These need not be created all at once, although tables must exist for the terrain types the characters have to enter during the course of an adventure. Different terrain types that can be used include the following:
* Aerial
* Arctic
* Bush
* Coatal
* Desert, hot or cold
* Farmland
* Glacier
* Grasslands
* Jungle, subtropical
* Jungle, tropical
* Lake
* Mountains, high
* Mountains, low
* Ocean, deep
* Ocean, shallows
* Parkland
* Plains
* Prehistoric
* Rain forest
* Salt marsh
* Steppe
* Swamp, tropical
* Swamp, temperate
* Temperate forest
* Tundra
Wilderness encounter tables can reflect more than just terrain. There are differences between the jungles of Africa and those of Asia or South America. Different areas of jungle (or plains or whatever) can have different properties in a fantasy world, too.
Furthermore, an area's level of civilization should be taken into account. There might be tables for settled farmlands, border areas, and barely explored plains. All cover the same type of terrain, but there are vast differences in the types of encounters.
==Special Encounter Tables==
In addition to tables for dungeons and wilderness areas, the DM can create others for any type of special situation he creates. The most common of these are encounter tables for towns and cities. These are not properly wilderness and certainly aren't dungeons. The players shouldn't expect to meet bands of ravening beasts intent on death and destruction (unless it's a very peculiar city!).
Town and city encounters will be with people, mostly player character races, of different social classes and occupations. Guardsmen, merchants, beggars, urchins, teamsters, and craftsmen plying their trade are all likely encounters for a city.
A single encounter table will do for most small villages and towns. Such places have a great deal in common, although the DM can certainly create distinctions between villages on the coast and those well inland.
Cities, however, tend to have unique characters. Just as Los Angeles is different from New York or Paris from Marseilles, different cities in a fantasy world should feel different to the characters. Each major city should have a unique encounter table to reflect these differences.
Indeed, even within a city there may be different encounter tables to reflect the character of the city's districts. The villas on the hillside are no less dangerous than the waterfront, but these dangers take more subtle and insidious forms.
In the end, there is no limit to the degree of subdivision that can be applied to encounter tables. Cities, individual districts, specific complexes within those districts, and buildings within those complexes could all have separate encounter tables. However, they do not need to. The DM should only concern himself with those areas he knows or thinks the players are going to frequent! There is no reason to do pointless work—the DM has enough responsibility already.
For example, suppose the DM decides to create tables for the Empire of Orrim. Orrim stretches from the Harr Mountains to the Sea of Faldor. North of it lies the Forest of Bane, a place noted for its evil denizens. Most of the empire is agricultural, but the mountain district is heavily devoted to mining. Several large, underground complexes have been built.
There are two major cities—Sulidam, the capital, located on the coast, and Coralport, a pirate stronghold on an island offshore. To limit his work, the DM decides to start the characters in a small village of the mining district, close to an abandoned mine (his dungeon).
First, the DM creates the following tables:
* Dungeon levels 1-4 (for the abandoned mine)
* Village encounters
* Black Opal Inn (the residence of the player characters)
After a while, the characters want to go exploring. Now the DM adds some new encounter tables to his collection. These include:
* Settled mountains (for low-level wilderness)
* High mountains (for more dangerous adventures)
* Settled plains (for when the characters travel to the capital)
Working in this manner, the DM gradually creates a complete set of encounter tables. When he is finished, his collection might look like this, in addition to those already mentioned.
* Farmland
* Forest of Bane
* Forest borderlands
* Mountain borderlands
* Settled seacoast
* Shallow ocean
* Waterfront district, Sulidam
* Nobles' district, Sulidam
* Artisan's district, Sulidam
* Slums, Sulidam
* Temple of Martens (a powerful cult of Sulidam)
* Sewers of Sulidam
* Emperor's Palace
* City of Crypts (a cemetery outside Sulidam)
* Dungeon of Theos (under an evil wizard's villa in Sulidam)
* Coralport
* Coralport jungles
* The Harpooned Whale, an inn of Coralport
* Hargast Mine (an opening to the Underdark)
By creating the tables gradually, the campaign world slowly begins to define itself and take shape before players' eyes.
==Spicing Up Encounter Tables==
There are several things that can be done to make encounter tables both easier and more exciting to use. Some of these are strictly for the convenience of the DM, making the job of running the game easier. Others are different ways to pose exciting challenges for players, keeping everyone from being bored.
The first trick is to include basic monster statistics along with each entry on an encounter table. While this means taking a little longer to set up an encounter table, it also means the DM doesn't have to stop and look up information as often in the middle of the game. A shorthand notation similar to the one given below can be used.
Creature #, PP #, AT #, THAC0 #, D #, AC #, HD #, MV #, special notes on attacks and defenses.
APP lists the number of creatures likely to appear. This is given as a die range.
AT is the number of attacks the creature can make.
THAC0 is the combat value of the creature (see Chapter 9 : Combat).
D is the damage caused by a successful hit; more than one entry may be needed here.
AC is the creature's Armor Class.
HD tells how many Hit Dice the creature has; hit points aren't given since this should vary from encounter to encounter.
MV is the creature's movement rate.
Special notes should remind the DM of any special abilities, magical items, or defenses the creature might possess.
For DMs willing to devote more time to advance preparation, another good trick is to slowly build a collection of file cards describing special encounters. Each card could have a more detailed description of a person, creature, group, or thing on it.
Once the DM has this collection, "Special Encounter" entries can be added to random encounter tables. When a special encounter occurs, the DM chooses a card from his collection and uses the detailed information there to role-play the encounter. Some possible special encounters include:
The den or lair of a creature, complete with a small map, short key, tactics, and special treasure. (For example, "The nest of a female wyvern and her brood located in an aerie on the side of a cliff. Woven into the nest are two suits of chain mail +1.")
A detailed description of an NPC, including weapons, magical items, spells (if any), goods, physical appearance, attitudes, companions, and perhaps even a mission or story. (For example, "The friar seeking companionship along a lonely trail who is really a bandit leading the party into a trap.")
A cunning trap describing detailed workings and effects. (For example, "A kobold deadfall meant to gather fresh meat rigged in an old mine corridor.")
A vignette complete with characters, actions, and motives. (For example, "A near riot breaks out on a city street after a band of Voorish outlanders, squabbling with a merchant, overturn his melon cart.")
The great advantage of these special encounters is that there is no requirement to use them at any given time. The DM can prepare such cards in his spare time and produce them whenever he needs them. Players will become convinced that the DM is a genius, and his game will never be dull.
Random encounters need not be limited to NPCs and monsters. All manner of things can be included, dangerous or just mysterious. Other possibilities for encounter tables include:
* Shrieks in the distance
* Traps
* Changes in the weather
* Rustling of nearby bushes
* Lights in the distance
* Celestial wonders
* Sudden gusts of wind
* The clatter of a rock falling from the ceiling
All of these help build atmosphere. Furthermore, if these are cleverly mixed with real encounters that begin in similar ways, players become attentive and involved. Exploring a dark, dank cave where hideous beasts may live, with only a guttering torch, should be a nervous and scary event. Adding "fake" random encounters will give players some idea of the uncertainty their characters experience. If nothing else, this kind of encounter will give players some respect for the risks their imaginary characters are taking!