Zone-Wide Environmental Effects

by Mike Shea on 27 August 2012

We DMs are always looking for new ways to shake up our encounters. Breaking down our encounters, we find the following components:

Changing up these layers makes each D&D battle unique and interesting. Today we're going to add another layer, another variable, that can change up battles even further: the zone-wide environmental effect.

A zone-wide effect

Zone-wide environmental effects change up an entire battle area. They cannot be avoided and they aren't focused around a specific spot in the encounter area. Instead, they affect all combatants within an ecounter. These effects change up a battle area, adding an additional effect to a battle that might otherwise seem stale. Here's a list of ten:

  1. Obscure Fog: A thick fog covers the area. Creatures cannot see further than 5 squares.
  2. Blood Rage: Murderous spirits whisper throughout the area. On any attack roll, creatures roll twice and take the higher result. All creatures within the area are vulnerable 5 to damage.
  3. Poison Gas: The area fills with a terrible poison gas. Each creature takes 5 damage per tier at the beginning of their turn. This damage increases by +1/2 level each turn.
  4. Polarity Charge: An electric field fills the area. Any creature that begins its turn adjacent to another creature takes 10 lightning damage per tier. Any creature that hits with a metal weapon inflicts an additional 5 lighting damage per tier.
  5. Arcane Instability: The fields of magic grow chaotic in this area. Any creature that uses an arcane power or item takes 10 damage per tier.
  6. Weak Dimensional Boundary: This area twists the boundaries between worlds. Any creature that teleports in this area takes 10 psychic damage per tier.
  7. Unholy Aura: The unholy nature of this area hinders the restoration of life. Any effect that would heal a creature instead heals half the amount. This may be avoided by the triggering creature spending an additional healing surge.
  8. Screaming Madness: Maddening screams fill the minds of all combatants. At the beginning of each creatures's turn, that creature moves its speed and attacks the nearest ally as a free action.
  9. Unstable Ground: The ground of this area rumbles and cracks, throwing opponents in disarray. While in this area, creatures cannot take immediate actions between turns.
  10. Searing Stone: The floor of this area burns with great heat. Any creature that moves less than two squares takes 10 fire damage per tier.

For a more old-school feel, consider rolling 1d10 to apply one of the effects above to your battle area.

Designing your own effects

When designing your own effects keep a few ideas in mind. First, any effect should be easy to run at the table. Choose simpler mechanics over complex ones. Try to choose mechanics that don't require die-rolls (yes, I'm aware I violated that rule a couple of times above). For zone-wide effects, keep the mechanics lightweight. You can use heavier and more powerful effects on specific areas of the zone such as magical runed rocks that give ranged attackers +10 lightning damage on ranged attacks. Choose effects that speed up combat and add threat. As much as a grasping roots effect sounds like a good idea, movement impairment usually just slows down the game. For this reason, adding damage onto both sides considerably speeds up combat without reducing the threat of the encounter.

Zone-wide effects as skill challenges

David A., diversionArchitect on Twitter, emailed in a good recommendation. He suggested giving players the ability to manipulate or disable these zone-wide effects as part of a skill challenge built into the encounter. For example, an unholy altar within a chamber may emit the unholy aura. As a standard action, a PC adjacent to the altar can disable the effect with a hard DC religion, endurance, heal, or arcana check.

This adds a whole other variable to the encounter and pushes PCs to actually run into the room and do things rather than hug a door or some other choke point.

Random dungeons for 4th edition

The website, Donjon, has excellent tools for building all sorts of random components, including a 4th edition random dungeon generator. Selecting the size of "fine" gives you a great single-session dungeon. Using the zone-wide effects above, you can add an entire additional layer to these random rooms, creating Diablo 3 style challenges for your gaming group when they just want to do some exploration, kill some monsters, and collect some treasure.

If you enjoyed this article, please take a look at Sly Flourish's Dungeon Master Tips and Running Epic Tier D&D Games. You can also pick up my two favorite encounter-building tools, the Dungeon Master's Kit and Monster Vault.

Send feedback to @slyflourish on Twitter or email mike@mikeshea.net.