Adventurers should always expect the unexpected but, as referees, how often do we deliver on that premise? Often we lean on the strange and unusual to produce moments of shock but, sometimes, the more shocking thing isn't what the players don't know but what they know, or thought they knew, delivered in a completely unexpected context.
Use your cast of characters
One way to achieve this is by re-surfacing established NPCs in place of new ones. You don't want to do this all the time and you want to be careful to avoid Scooby-Doo style reveals of every villain.
Who is it?
When a known NPC is revealed somewhere that they don't belong, it has the great effect of revealing potential hidden lives and motivations for a character that puts them in a new context. the best part is that it comes with next to no cost. While the party is debating how the town miller ended up on the third level of the dungeon, you can have fun exploring this new reality with them. When a character is revealed in a wilderness or dungeon encounter, roll to see who it is:
| 1d6 | Who is it? |
|---|---|
| 1-3 | A stranger. |
| 4 | A local villager. |
| 5 | A local authority or religious figure. |
| 6 | An ally, friend, or mentor. |
