Rulebook: The Battlefield

Okay, this is an area where Nutshell will differ significantly from 3e, 4e, SWSE, and the like...

Every bit as important as the opponents that the heroes face in a fight is the question of where the battle takes place. Terrain, traps, and other features can radically influence the outcome of a combat, swinging a battle one way or the other.

Zones of Combat

The battlefield will be broken into broad zones. The boundaries between zones may be sharply delineated or they may be more nebulous. Characters may be positioned within a zone, or they can position themselves on the boundary between zones.

At the outset of combat, the DM will quickly describe the battlefield, outlining the various zones of operation. The number and type of zones will depend on the specifics of the combat (and even the combatants!), and it is entirely possible either that new zones will be defined as the combat progresses or, indeed, that entirely new zones will come into existence during a combat!

Characteristics of a Zone

For the most part, the DM is free to define zones as he sees fit. However, the following guidelines should be considered when defining zones:

• A zone should typically have a single dominant terrain type, allowing it to be easily defined. "The floor", "the walls", "the stairs" would all make for good zone descriptors. In general, a single zone should not include all of the above.
• Zones should be reasonably small. The combat rules allow for a character to cross from an arbitrary point within one zone to an arbitrary point in another in a single Move action, and so the zone definitions should recongnise this. A zone with clear terrain should not be more than about 50 feet across; a zone with impeded movement should probably be even smaller.
• Where possible, zones should have reasonably clear boundaries. This can be difficult for a combat taking place on a large, open field, but such combats should be rare in any case. Where a clear boundary cannot easily be established, it is recommended that some sort of sketch be made of the battlefield, showing the boundaries between the zones so that the players can visualise the action.

Moving Within a Zone

Typically, characters can use a single Move action to move from any position within a zone to any other position. This includes movement from any position within the zone to a position on the boundary with another zone. Characters are assumed to move quickly, but also with reasonable care, and so are not at particular risk from known threats.

There are a few exceptions to this:

1. An enemy combatant may have a Readied action or be able to use a Reaction (such as "No You Don't") to prevent you from moving.
2. When travelling in a zone with impeded movement, the character must make an Athletics check, or be unable to move.
3. If the zone contains any unknown threats, such as hidden traps, the character must make a Saving Throw or spring the trap.

Moving Between Zones

Typically, characters can use a single Move action to move from any position within a zone to any position in a neighbouring zone. In order to do this, characters are assumed to be moving as quickly as possible, and so are at greater risk than when simply moving within a zone.

If either your current zone or your new zone has impeded movement, you cannot use a single Move action to move beyond the boundary between zones. Likewise, if an enemy has a Readied action or a suitable Reaction to attempt to stop you from moving at all, this automatically prevents you from crossing the boundary of your current zone.

In addition:

1. If either your current or new zone contains any known dangers, such as traps or environmental conditions, you must make a Saving Throw to avoid those dangers.
2. If either your current or new zone contains any unknown dangers, such as hidden traps, you automatically trigger them in your haste to move.

Crossing the Boundary

In most cases, crossing the boundary from one zone to another is a trivial matter; you simply step from one to the other. However, if the boundary is somehow difficult to traverse, and especially if an enemy combatant attempts to block your path, you must make an Athletics check to cross from one zone to the next.

When crossing a fixed boundary, such as a fence or door, the DC for the Athletics check will be determined by the boundary condition itself. For example, a fence may be DC 15, while a stuck door is DC 20. Typically, a character can automatically cross a fixed boundary as a Move action.

When crossing a boundary impeded by an enemy combatant, the Athletics check must beat the opponent's Combat Defence. Note that where the boundary is unusually narrow, such as a single doorway between two rooms, the presence of an enemy combatant may impose disadvantage on the Athletics check. Typically, a character cannot automatically cross a boundary guarded by an enemy. However, dedicating a Move action to the effort grants advantage on the Athletics check.

Where multiple boundaries apply, a single check should be made against the single highest DC. Only if the conditions are particularly difficult should any additional modifier be applied; in such a case, disadvantage should be applied to the Athletics roll.

Crossing Multiple Zones

If a character absolutely, positively has to get from one zone, through a neighbouring zone, and into a third zone, he can run at full speed. Doing so requires that none of the three zones have impeded movement, and that both the boundaries be clear of obstructions and defenders.

In such a case:

1. The character must make an Athletics check against a DC of 15. Failure indicates that the character cannot move beyond the boundary between the second and third zones.
2. If there are any known or unknown dangers in the three zones, the character automatically triggers them. He is moving too quickly to avoid these dangers, even if he is aware of them.

Impeded Movement

Some zones have rough terrain, or otherwise impede movement. In such a case, moving within the zone requires an Athletics check. Failure on the check means that the character must remain where he is. The DC of the Athletics check is determined by the nature of the terrain.

If a zone has impeded movement, a character cannot both pass the boundary and move within the zone as a single Move action. In such a case, the character's movement ends at the boundary between the zones.

Defining New Zones

Sometimes, the actions of one or more combatants will reveal a need for new zones to be defined. For example, if a combat occurs on the floor of a hall, with a set of stairs leading to a balcony, the DM may define three zones at the outset (floor, stairs, balcony). However, if one of the PCs decides to climb the walls to the balcony, this indicates the need for a fourth zone (walls).

In such a situation, the DM should simply define the new zone and add it to the battlefield. After all, the actions of the PC haven't created the new zone - it was there all along, it just wasn't noticed until now!

Creating or Destroying Zones

Conversely, the actions of one of more combatants may cause the creation of entirely new zones of combat. This may occur if the Wizard casts a wall of fire spell, for example, or if a band of hobgoblins move to encircle a single character (creating a "surrounded by hobgoblins" zone).

Equally, the events of the combat may cause a zone to simply cease existing, for example at the expiry of that wall of fire spell.

When such events occur, the DM and the players should work together to define the new zone, if applicable, to determine the conditions for movement within the zone, and at the boundaries, and to determine which combatants are within the zone.

An Example Battlefield

The PCs are travelling in an airship, heading North. As they travel, they are attacked by drow slavers on dragonback!

The battlefield is broken into several zones:

- The bulk of the action takes place on the main deck, a large, clear area with a Lightning Thrower in the middle.

- The main deck borders the fore deck, where a ballista is to be found.

There are two boundaries between these zones - a small set of stairs (no DC, but these can be blocked by a character), or by climbing up from fore- to main decks (DC 15) or dropping down from main to fore- (1d6 damage).

- There is a below-deck area, which provides access from one part of the ship to another. No combat takes place in this area, but it is important for movement purposes.

Later in the combat, one of the characters jumps from the main deck onto the back of one of the dragons. This identifies a "dragonback" zone, that immediately ceases to have any connection to the other zones. However, the "dragonback" zone isn't new; it just hadn't been identified previously.

Likewise, later in the combat one of the heroes uses a wall effect to cut the main deck in two. This effectively creates "main deck front" and "main deck aft" zones, with the wall providing a boundary between them.