In this guide, you will learn a set of monster AI rules for solo DnD encounters. The core idea is simple: the monster uses a simple priority system to choose an appropriate action and the right target. Once the enemy ability and target have been selected, combat resolves as per D&D rules. When I designed this system, I looked at three board games for inspiration: Gloomhaven, Middara, and Dungeon of the Mad Mage. I adjusted their AI rules so that you can use them with D&D 5e.
Monster AI action priorities
During the monster’s turn, the monster prioritizes its actions from highest to lowest as follows:
Making saving throws and removing conditions.
Lair actions (if within a lair).
Defensive spells on self (if needed), followed by offensive spells against enemies.
Special abilities such as summonings, eye beams, and other special attacks.
Ranged weapon attacks until the enemy enters melee range.
Melee attacks until the opponent leaves melee range.
When it’s an opponent’s turn, the monster prioritizes:
Legendary actions, followed by reactions.
Monster AI rules during combat
When it’s the monster’s turn, it targets the PC party member closest to it. If there are two or more targets within the same distance, choose the one with the highest initiative.
Choose an attack based on the actions available to the monster and which of its actions have the highest priority. If there there are two or more actions with the same priority, choose one at random.
Move the monster towards the target until it’s within the range of the attack.
Roll the appropriate dice for the attack.
Choosing attacks and targets randomly with dice rolls
A player can randomly select a monster attack by assigning a number to each action and rolling the appropriately numbered die. Standard dice are the typical d4, d6, d8, d10, d12, and d20. However, to select a random attack or target, you can use dice that also cover other numbers such as d2, d3, and d5.
These are non-standard dice that use a pre-existing die, but with a simple formula. To roll 1d2, roll a d4, divide the result by 2, and round it up. To roll 1d3 and 1d5 you use the same formula but use a d6 and d10 respectively.
Important Monster AI rules
Monsters always target the closest opponent. If a monster has more than one target, it will prioritize the opponent with the highest initiative.
Monsters do not attack invisible or stealthed characters if they’re successfully hidden.
Monsters stop attacking characters that have been reduced to 0 health points.
If a monster needs to make a saving throw, break a spell effect, or remove a condition, it will prioritize it first before everything else.
Monsters will always try to establish a line of sight when making a ranged attack against an opponent.
Monsters with ranged attacks move until an opponent is within the range of their attack. If the opponent is already within range, discard any movement actions unless the attack requires line of sight.
Monsters with ranged attacks will attempt to hide behind the closest terrain feature that provides cover after completing their actions.
Monsters always seek to avoid visible traps and dangerous terrain. They will move around such threats during combat.
In this guide, we will show you how to use our Adventure Generator for D&D and other fantasy roleplaying games. The adventure generator uses percentile tables to create a basic outline for an adventure. The player can then use this outline as a starter for a campaign or other important quest. The adventure generator uses seven tables to create the plot for your game.
These seven tables, when combined with the background lore of your setting, can provide many hours of adventuring for the solo player. These hooks can serve as inspiration when starting a game, or as a way to create other major quests. This tool can also be used alongside ChatGPT to help create text-based adventures. Our Solo DM Guide Part 3 – ChatGPT As Assistant AI Dungeon Master covers this method in detail.
The Adventure Generator is extremely useful and you can use it in many different ways. Need to do a favour for an NPC? Use the Adventure Generator to find out what they want from you. Looking for work because you’re low on funds? Use the Adventure Generator to find out what work is available.
What are Adventure Generators?
Adventure generators are tables that help you to create a random adventure. There are many tables like these online and feature often in OSR resources. If you want to have an idea for an adventure you simply throw a die and consult a table. Some players may already have an idea for an adventure before the session starts. This adventure idea can come from a film, book, or video game. In this case, an Adventure Generator isn’t necessary. Use your idea instead.
The adventure generator uses four adventure types when generating a plot.
Caught up in events
The adventurers are caught up in events that are beyond their control. A character might be struck down by a curse or a party member might’ve seen something they shouldn’t have.
The characters are hired by an employer to do a job. They might have to look for a missing person, hunt down a dangerous creature, or mediate peace talks between rivals.
The party needs to explore a location to achieve a goal. They might be looking for a lost treasure, a creature’s lair, or a place of mystical power.
The adventurers are asked to help a community in need. This might involve overthrowing a tyrant, investigating a cult, or saving a town from disaster.
The Who table
The Who table details people who need help or are directly involved in the adventure. This table gives brief descriptions of non-player characters that can act as quest givers in a campaign. However, in certain adventures, the Who table can also be used to generate enemies that work against the player.
To discover how much power an individual wields within the campaign (such as nobles, government officials, and military members) roll a 1d6. A result of 1 indicates a weak or low-ranking member. A result of 6, on the other hand, indicates an extremely powerful individual, such as a king or general.
The Opposition table
The Opposition table contains enemies that oppose the adventurers in the campaign. These can range from powerful entities to organizations that want to prevent the party from reaching the quest objective.
Roll a 1d6 to discover your opposition’s power. A result of 1 indicates that a weak individual or group. However, a result of 6 indicates an extremely powerful enemy. How they oppose the adventuring party should be based on the campaign setting and the player’s personal preference.
Using the adventure generator
The player can use the adventure in one of two ways. The first method involves rolling a d100 and consulting the various tables.
Begin by rolling a die or choose a quest type on the Adventure Type table. Then roll a d100 a second time and consult the tables detailing the adventure type. Exploration adventures have an Exploration Location and Exploration Goal table. These tables describe where the adventure takes place and why the adventurers are exploring that location.
If you need a quest giver, roll on the Who table. To find out who opposes or works against you during an adventure, roll on the Opposition table. Then roll a 1d6 to determine how powerful the opposition is that you’re facing. A result of 1 indicates a weak opponent, while 6 indicates en extremely powerful opponent.
Alternatively, instead of rolling on the various tables, the player can simply choose the options that appeal to them. If the player already has a quest giver in mind, then rolling on the Who table might not be necessary. Similarly, if the player already has a suitable enemy in their campaign, then rolling on the Opposition table might not be needed.
When you have the various plot elements, adapt them to your campaign setting’s lore and locations. Use these plot elements to create a basic synopsis for your adventure.
Peter wants to create an adventure that takes place in the Forgotten Realms campaign setting. He decides to create an adventure for his party by rolling on the tables in the adventure generator.
On the Adventure Type table he rolls a 57. His party needs to explore an area. On the Exploration Location table he rolls a 98. The location is an ancient castle. To find out why his party is exploring this location, Peter rolls on the Exploration Goal table and gets 80. He needs to explore this castle to find a lost treasure.
Peter wants a quest giver for the adventure, so he decides to roll on the Who table to see who hired the party. Peter rolls 62, a religious figure needs his help. To find out how powerful this religious figure is, he rolls a 1d6 and gets a 4. The religious figure has some influence, but isn’t that powerful in their church.
To finish of the adventure outline, Peter rolls on the Opposition table to find out who opposes the party. He rolls 91. The party is opposed by a mystical entity. To discover how powerful this entity is, Peter rolls a 1d6 and gets 1, the entity is weak, but can still cause problems.
Peter decides that his party is hired by a Dawnmaster of Lathander to seek a lost artefact stolen by an imp. The imp is hiding in an ancient castle near the city of Baldur’s Gate.
Create side-quests with the legacy Adventure Generator
The legacy Adventure Generator is a part of the Solo Gaming Tool and uses a pack of playing cards to generate adventures. The legacy Adventure Generator is useful for creating quick side-quests during a game instead of at the start of the session. There are four categories of quests in the legacy version, one for each card suit: event-based (Spades), item-based (Hearts), NPC-based (Diamonds), and location-based (Clubs). The card suit determines the objective and focus of your quest.
Here are the oracles in the legacy Adventure Generator.
How to use the legacy Adventure Generator
To use this tool, draw a card, consult the oracle, and follow the instructions on the oracle.
For example, drawing a 4 of Spades gives the objective as “protect someone involved in …”.
To find out the second part, the subject of the adventure, follow the instructions listed under the suit. In our example, because we drew a Spade so we must draw another card and consult Oracle 8. Oracle 8 contains a list of possibilities. If we draw a 7 of Hearts it gives us “… a mystical event”.
Together the 4 of Spades and 7 of Hearts give us “protect someone involved in a mystical event”. You can use this short adventure hook any way you see fit in your campaign. You can use it as is and use other oracles to flesh it out, or you can use it as inspiration for coming up with your ideas.
You walk into a tavern and ask the innkeeper if he knows of anyone who has work for you. The Fate Roll says “yes, and …”. The innkeeper points you in the direction of a stranger sitting alone at a table. You ask them, “I hear you have work, what do you have to offer?”. To find out what your employer wants you to do, you decide to use the Adventure Generator.
You draw a 6 of Spades. Oracle 7 gives you “Circumvent… ”. The oracle instructs you to draw another card and consult Oracle 8. You draw a 5 of Spades. This gives you “… a trial.” Together they give you “circumvent a trial.”
The stranger tells you that he needs someone who can get their hands dirty. A friend of his has been arrested and he wants to break him out during his trial. Whether you accept the stranger’s offer or report it to the authorities is up to you.
Choosing locations for location-based adventures
The suit of Clubs refers to adventure objectives that involve locations. If you draw the 5 of Clubs, you are given “Destroy…” as an adventure objective. You are then instructed by the Oracle to choose a location.
Make a list of possible locations that you think would be suitable to destroy in your setting. You may have come across a bandit camp, a cult fortress, an infernal stronghold, etc. Roll a die to select which one you will attack and try to destroy. If you can think of only one suitable location, then choose that one.
You meet an agent in Waterdeep who has a task for you. To find out what she wants from you, you decide to use the Adventure Generator . You draw a 9 of Hearts which gives the objective as “Infiltrate …”.
Based on your setting you decide 4 possible locations would make sense: (1) A Zhentarim stronghold, (2) a Shadow Thieves hideout, (3) a corrupt merchant’s guild, and (4) an enclave of Red Wizards. As a result, you decide to roll a 1d4 to select the location. You roll a 2, the Shadow Thieves hideout.
You can interpret this as follows: the agent wants you to infiltrate a Shadow Thieves hideout in Waterdeep.
How to make the most of the Adventure Generator
Use these adventure hooks as inspiration, don’t follow them slavishly. If you come up with a better adventure hook, use that one instead. You are your own GM when playing solo or cooperatively. These rules and tools are intended to help you, not replace your judgment or creativity.
When you’re satisfied with your adventure hook write it down. It will provide context to your actions as well as a clear goal for your character to strive for. This will form the core of your story and can develop into an entire campaign. It will evolve in unpredictable ways and provide more inspiration for more adventures to come.
The Random Event Oracle introduces unanticipated scenes into your game. Whenever you use the Fortune Oracle and draw an Ace or Joker, a random event enters the scene. This introduces variety and unexpected twists into your adventure. The oracle consists of phrases that describe commonly occurring story motifs that can become a part of your adventure. This tool forms part of the Solo Gaming Tool.
When a random event enters your game through the Fortune Oracle, draw a card and look at the story motif associated with it. Improvise a scene based on the motif and introduce it into your game.
The Random Event Oracle was inspired by The Adventure Crafter by Wordmill Games.
To help you create your scenes, I included a scene idea with each card to help guide you. Use the logic of your story and setting when applying the random event to your adventure.
2 of Spades
Event: A mysterious event
Scene idea: Something strange or out of the ordinary is happening or has happened.
3 of Spades
Event: A necessary resource runs out
Scene idea: A resource that’s necessary to a character or group of characters has run out.
4 of Spades
Event: Impending doom
Scene idea: A character or group of characters will meet their doom.
5 of Spades
Event: Shady dealings
Scene idea: A character is engaging in criminal or otherwise suspicious dealings.
6 of Spades
Event: An ambush
Scene idea: A character is being ambushed or is ambushing another character.
Event: An abduction
Scene idea: An abduction or attempted abduction is taking place.
8 of Spades
Event: A work-related gathering
Scene idea: A gathering of workers or employees
9 of Spades
Event: A figure from the past
Scene idea: A figure from the past appears. This can range from a person in a character’s personal past to a historical figure from a nation’s past.
10 of Spades
Event: An unfortunate event
Scene idea: Something unfortunate happens to a character. This can also mean an unfortunate event from the past.
Jack of Spades
Event: A problem returns
Scene idea: A problem from the past returns. This can range from a personal problem to a problem on a large scale.
Queen of Spades
Event: A savior
Scene idea: A savior has entered the scene or a character needs a savior.
King of Spades
Event: Official business
Scene idea: A character is on official business. This includes all government officials.
Ace of Spades
Event: A mysterious item
Scene idea: A mysterious item is the focus of the scene. This can be any strange or unknown item.
2 of Hearts
Scene idea: Religion or religious figures form the central theme of the scene.
3 of Hearts
Event: The need to hide
Scene idea: Characters need or try to hide.
4 of Hearts
Scene idea: A character is engaging in conflict with another. This can range from a simple verbal disagreement to an outright fight.
5 of Hearts
Event: Escort duty
Scene idea: A scene where a character needs or is performing escort duty.
6 of Hearts
Event: A just cause gone wrong
Scene idea: Something that is righteous or just has negative consequences.
7 of Hearts
Event: A confrontation
Scene idea: Characters are confronted either literally or figuratively. This can range from being confronted by enemies to confronting injustice in a community.
8 of Hearts
Scene idea: A character, object, or anything else is destroyed. The destruction can range from relatively mild to outright desolation.
9 of Hearts
Event: A character disappears
Scene idea: A missing person forms the focus of the scene. This can range from a missing stranger to an important friend or associate.
10 of Hearts
Event: A rare or unique gathering
Scene idea: A gathering is taking place that’s rare or unique.
Jack of Hearts
Event: Someone is where they shouldn’t be
Scene idea: A character is somewhere they don’t belong.
Queen of Hearts
Event: Useful information from an unknown source
Scene idea: An unknown source provides useful information to a character.
King of Hearts
Event: An influential person
Scene idea: An influential person has entered the scene. This person can be an influential leader or an influential artist or expert.
Ace of Hearts
Event: A scapegoat
Scene idea: A character is used as a scapegoat for a misdeed.
2 of Diamonds
Scene idea: A scene of death. This includes funerals, victims of crime, or any other form of death.
3 of Diamonds
Event: A group is in trouble
Scene idea: A group of characters is in trouble. This can range from a group of single individuals to large organizations.
4 of Diamonds
Event: Help, for a price
Scene idea: A character provides or asks for help, for a price.
5 of Diamonds
Scene idea: A character is experiencing an injustice.
6 of Diamonds
Event: A standoff
Scene idea: A standoff is taking place between characters.
7 of Diamonds
Scene idea: A character is committing theft or theft has taken place.
8 of Diamonds
Scene idea: A character is being followed.
9 of Diamonds
Event: Meeting friends
Scene idea: A character meets friends or allies.
10 of Diamonds
Event: Asking for help
Scene idea: A character asks for help.
Jack of Diamonds
Event: A mysterious new person
Scene idea: A mysterious new character is the focus of the scene.
Queen of Diamonds
Event: Fraud and deception
Scene idea: A character is committing fraud or deceiving another character.
King of Diamonds
Event: An argument
Scene idea: An argument is taking place between two or more characters.
Ace of Diamonds
Event: An emotional gathering Scene idea: Characters are engaging in an emotional gathering. This can range from joyous gatherings to mob violence.
Immersion is an important aspect of roleplaying games, and with music you can boost it. Recently, we played a cyberpunk game using the Interface Zero 2.0 game for the Savage Worlds system and to get really into the game, we needed good music.
These artists make incredibly immersive science fiction music and I recommend any of Solar Fields’ albums if you’re looking for futuristic style ambient music.
This mix is just under two hours, which is perfect for the length of sessions we’ve been having, but perhaps you want longer sessions. I’ve created a playlist using some of these tracks, as well as around 4 extra hours of cyberpunk-themed tracks on Tidal, which you can find here, as well as on Spotify, which is still a work in progress. I’ll recreate the same playlist on other platforms such as Apple Music as well as YouTube, so check back later for links!
You can even boost immersion further by using headphones to block out unwanted background noises, but be sure to keep the volume low enough not to damage your hearing.
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