Certain spells and special abilities have an area effect of Line 12. This particular area of effect causes more confusion than any of the others. Cones and radius areas are strictly defined. Players can place a template directly on the battlemat and see exactly which squares are affected. Line 12, on the other hand, can affect a different pattern of squares each time a spell is cast, even if it's the same spell each time. It all depends on how the spell is targeted.
To clear up the confusion, this article will break the Line 12 rules into manageable pieces and look at examples of various patterns.
Here's what the Line 12 rule states (page 39 of the War Drums rulebook) --
A spell or effect with a range of line 12 affects creatures in a straight line away from the acting creature toward the nearest enemy or ally. A line does not affect creatures more than 12 squares away. Trace a line from a corner of a square in the acting creature's space to a different corner of a square in the target creature's space. The line affects all squares that the line goes through or touches until it touches or crosses terrain that blocks line of effect. (Don't count the corner where the line starts.) A line usually continues to its full range, and even goes past the target and possibly affects more creatures, but stops as soon as it touches (at some point other than the origin) or crosses terrain that blocks line of effect.* The same corner can't be chosen for both the starting point and the target of the effect.**
* This sentence matches the updated, online version of the War Drums rulebook, not the printed version.
** This clarifying sentence is added in accordance with the online errata. It does not appear in the printed rulebook.
That paragraph is packed with information. Let's examine it one point at a time. We'll start with the simplest statements and work our way up.
"A line does not affect creatures more than 12 squares away."
If a creature is more than 12 squares from the origin corner of the line, then a line can't hit it under any circumstance. That applies to the nearest square of a multi-square creature. A Large creature, for example, covers four squares. If any one of those squares is within 12 of the caster and is touched or crossed by the line, then the creature is affected.
Cover has no effect on this range. Distance is counted just like movement except that difficult terrain doesn't cost extra and the path can be counted diagonally past a corner.
"… the nearest enemy or ally"
A spell or special ability is always targeted against a specific, single creature.* According to page 22 of the rulebook, "Ranged spells (and special abilities) can target the nearest enemy or the nearest ally." "Nearest enemy" is further defined on page 40.
It's crucial to recognize that there's no distinction between harmful and beneficial spells. That is, a spell that is clearly harmful to the target can be aimed at one of your own creatures, and one that is clearly beneficial can be targeted against an enemy creature. In the case of line 12, you might choose to do this because, by targeting your own nearest creature, you can hit three or four enemy creatures with the line, whereas if you targeted the nearest enemy, you might hit only one or two.
"Nearest enemy or ally" is counted the same as the overall range. Cover has no effect. Distance is counted just like movement except that difficult terrain doesn't cost extra and the path can be counted diagonally past a corner.
* Under certain conditions, this rule is altered. Those conditions are spelled out in the specific spell or special ability description.
"Trace a line from a corner of a square in the acting creature's space to a different corner of a square in the target creature's space."
Most of the time, this is straightfoward. You can pick any corner in your own creature's space and any corner in the target creature's space. You must have line of sight to the target creature, but you don't need line of sight to the target corner.*
Diagram 1 shows every possible line that can be traced from the Cormyrean War Wizard to the Duergar Slaver and the Large Duergar. Note two things --
First, the acting player can choose an origin corner such that the line crosses his own creature's space. This can be done even when it means that the acting creature will be harmed by its own spell or special ability.
Second, the target corner can be an internal corner if the target creature covers more than one square. If the target is the Large Duergar, for example, the target corner can be the central nexus of all four squares that the Large Duergar covers.
The phrase "a different corner" becomes important when the acting creature and the target creature are in adjacent squares. The target corner must be different from the origin corner. They can't both be the same, shared corner. Diagram 2 shows this. If the Cormyrean War Wizard chooses the white corner as the origin for a line, then the target corner must be one of the green corners. This point is reinforced by the sentence that is added in the errata -- "The same corner can't be chosen for both the starting point and the target of the effect."
* "Can see" is not defined in the definition of Line 12. It is stipulated, however, in the definition of Nearest Enemy on page 40 of the rulebook.
"The line affects all squares that the line goes through or touches …"
This is the point where most players get confused, because it's where each line becomes different.
The very simplest sort of line is shown in Diagram 3. It is a perfectly straight line covering exactly 12 squares between the caster (Cormyrean War Wizard, upper left) and the target (Dark Talon Champion , upper right), which is 12 squares away. It is, however, a rarely seen line. The only way it can happen is if the target is in the same row or column of squares as the acting creature, and the origin and target corners are on opposite sides of that row or column. The affected squares are shown in green, and the range to each square is indicated.
The second simplest type of line is shown in that same diagram. It is a line targeted at a 45-degree diagonal from the acting creature's space. Spaces that the line passes through are shown in green. Note that, even though the line has a length of 12, it passes directly through only 8 spaces. This is because range is counted the same as movement, counting double for every second diagonal space. The 'range count' is indicated in each space.
The line also affects spaces shown in yellow, even though it doesn't cross those spaces. The line touches each yellow space at one corner. According to the definition, a touch is all that's required. Even though the line directly crosses only 8 spaces, it affects 22! Creatures in any of those 22 spaces take the full effect of the line.
See Diagram #4. It shows a situation similar to the simplest example of a line. Here, the line is being cast between an origin point and a target corner that are on the same side of a single row. That sends the line exactly between two rows of squares. Because the line touches both rows, both rows are affected, even though none of the affected squares are directly crossed. Instead of affecting only 12 squares, this line affects 24 squares.
Of course, lines aren't always drawn at perfect 90 degree and 45 degree angles. In fact, those are the least common cases. Most lines are drawn at odd angles, and that creates odd patterns of affected spaces.
In Diagram #5, the line is drawn at an angle that causes it to directly cross 11 squares and touch four others. All 15 squares are affected equally. The Large Duergar is affected as much as the Duergar Slaver, even though the line doesn't directly cross any of its squares, and only one of the squares it occupies is affected.
A second point to note from Diagram #5 is where the double count for a diagonal space occurs. The first square of a line is always counted as a diagonal square. In effect, because the line originates at a corner, it is considered to 'enter' the first square at a diagonal.
Finally, in Diagram #6, you can see that the range of the line is counted along the shortest path. Not every square crossed by the line needs to be counted. (This path is identical to the one used in the Line 12 example from page 39 of the rulebook, although rotated 90 degrees clockwise.)
"… until it touches or crosses terrain that blocks line of effect."
Line of effect is defined as "nearly always the same as line of sight." Only fog/smoke, forest, and walls block line of sight. Of those three, however, only walls block line of effect. That means, if a line is targeted against a creature the caster can see, it can affect creatures that the caster can't see because they're hidden by forest, fog, or smoke, provided the line crosses or touches their spaces.
Line of sight and line of effect end immediately at the point where the line touches blocking terrain. Squares that touch only that point are not affected, as shown in Diagram #7. Squares A and B are touched only where the line hits the blocking pillar (which is the same as a wall), so they are not affected by the line.
"Don't count the corner where the line starts."
A square that is touched only by the line's origin corner is not affected by the line. Four squares will always be touched by the line's origin.* Three of those squares are not affected, however, because that corner is the only part of the square touched by the line's origin. If a line extended directly down the side of a space, then that space would be touched at more than the origin corner, and it would be affected (as shown in Diagram #4).
* Unless the origin corner is directly on an edge or corner of the battlemat.
If you have questions about how other D&D Miniatures rules work, you can ask them in the D&D Miniatures forum. You can also find a host of clarifications through the Errata and FAQ page.
About the Author
Steve Winter is a web producer, writer, and game designer living in the Seattle area. When not lost in fantasy worlds of his own devising, he drops in on other people's fantasies. That's been interesting ...