Your players are at a crossroad where the castle of certain evil death that you have been working on for the last month is in one direction and the forest of you have no idea what’s in there is in the other direction. Every so often I get asked by my players “Do you mean to do that?” And quite honestly the answer is normally no. It can be a lot of fun just pulling things out of thin air but a word of caution to the newbie GM – do not do this often or your players will figure it out. There are some that can pull off various encounters on the fly like they were born to it, and they probably are natural storytellers. I am one, but not everyone has this ability.
So how do you make encounters on the fly without the players catching on? The one word answer is to be realistic with your choice of encounters. Now this does not mean that you have to be specific to the “challenge rating” or “level” or anything else of the party. To me if it makes sense that a dragon would be encountered wandering around his lair and your party is only level one then they might encounter that dragon. Granted that’s an extreme but if the party goes into the swamp of dragon death then they should know they could encounter a dragon there.
Dragons? I thought you said be realistic – come on - what does being realistic really mean? Well to me it means keeping the paradigm of the fantasy setting intact. As an example, if the players are entering a town that is rumored to be filled with thieves it is not out of the ordinary for you to pull out the npc guides in the back of the GM book and just use the thieves right from the book if things get bogged down.
Secondly, always drive the story. What I mean by this is that even though you are pulling things out of the void you want to make sure that there are pieces of the story embedded within the seemingly random encounter. For me some of the best novels I have read have had encounters in them that seemed like mere chance but happened to be using the classic elements of storytelling – foreshadowing and flashbacks.
Example: Let’s say that the overarching storyline is about the players trying to gain the attention of an evil king’s advisor who they have befriended so that they can ferret out the king’s evil plans. The game has bogged down and you are not prepared for the night but you know that in your story that a runner is to deliver a note to the visor on behalf of the king. As the players continue through their day they are accosted by a group of common folk who demand that they saw one of the players outside of the bedchambers of their wife. This is a plant by the king to get the players into jail. A fight ensues with the king’s guard attempting to arrest the party. During the fight the players happen to see the runner and are tipped off by overhearing a conversation that he is heading to the visor. A chase ensues as the players are able to overtake the runner and stop him from delivering the note. All the while the king’s guards are fast approaching just as the visor, from hearing the commotion, runs out of his chambers and bumps into the players. An interesting easy challenge but the players have to think fast – they have the note but have been convicted of a crime. Will their friend help them?
The third piece of encounters on the fly is to be balanced to your expectations. Random encounters should always be fun and energetic and hopefully not too damaging on the players. I know I kidded about using dragons earlier but the unofficial rule of encounters is that they should take up a specific percentage of the player’s overall resources that you want them to take up. Should you decide to run a random encounter that takes 100% (or more) of the player’s resources then expect it to last all session or to do a good amount of downtime roleplaying as they recoup their magic and lick their wounds from the ‘random’ encounter.
A fourth part of random encounters is to give reward. No player likes taking on even a goblin and not getting something in return. This is especially true of reward-based games like Pathfinder and DnD. These types of games award treasure but at least give them some experience at a minimum. Also be sure to reward creative players. Encounters do not always have to be about fighting. I have had some great encounters that were randomly pulled from the void that entailed roleplaying and some social rolls which turned out to be game changers.
If you are not good at randomly coming up with things you can write down some random encounters n a piece of paper and assign a die value to it. Whenever you need a random encounter roll the die assigned and review the random encounter table. It could be as simple as a list with a one word encounter or a list with plot points listed for possible continuity of the story.
1) 1d4 goblins after food (goblins are being forced out of the forest by the king’s sorcery)
2) Lost dog (dog belongs to king and returning it will grant the players an audience with his daughter)
3) King’s guards (looking for people out after curfew)
4) Merchants looking for their stolen property
6) Dragon (Dragon is upset about the king mining in his mountain range)
7) King’s son (King’s son is trying to find the missing letter)
8) 1d6 thieves (they are just thieves nothing special)
Random encounters can be generated from a table or you can make them up on the fly. The key is to make them realistic, fun, challenging, and rewarding.