Counterspells
This ring might seem to be a ring of spell storing upon first examination. However, while it allows a single spell of 1st through 6th level to be cast into it, that spell cannot be cast out of the ring again. Instead, should that spell ever be cast upon the wearer, the spell is immediately countered, as a counterspell action, requiring no action (or even knowledge) on the wearer’s part. Once so used, the spell cast within the ring is gone. A new spell (or the same one as before) may be placed in it again.
Moderate evocation; CL 11th; Forge Ring, imbue with spell ability; Price 4,000 gp.
Aiming A Spell
You must make some choice about whom the spell is to affect or where the effect is to originate, depending on the type of spell. The next entry in a spell description defines the spell’s target (or targets), its effect, or its area, as appropriate.
Target or Targets
Some spells have a target or targets. You cast these spells on creatures or objects, as defined by the spell itself. You must be able to see or touch the target, and you must specifically choose that target. You do not have to select your target until you finish casting the spell.
Area
Some spells affect an area. Sometimes a spell description specifies a specially defined area, but usually an area falls into one of the categories defined below.
Regardless of the shape of the area, you select the point where the spell originates, but otherwise you don’t control which creatures or objects the spell affects. The point of origin of a spell is always a grid intersection. When determining whether a given creature is within the area of a spell, count out the distance from the point of origin in squares just as you do when moving a character or when determining the range for a ranged attack. The only difference is that instead of counting from the center of one square to the center of the next, you count from intersection to intersection.
You can count diagonally across a square, but remember that every second diagonal counts as 2 squares of distance. If the far edge of a square is within the spell’s area, anything within that square is within the spell’s area. If the spell’s area only touches the near edge of a square, however, anything within that square is unaffected by the spell.
Burst, Emanation, or Spread
Most spells that affect an area function as a burst, an emanation, or a spread. In each case, you select the spell’s point of origin and measure its effect from that point.
A burst spell affects whatever it catches in its area, even including creatures that you can’t see. It can’t affect creatures with total cover from its point of origin (in other words, its effects don’t extend around corners). The default shape for a burst effect is a sphere, but some burst spells are specifically described as cone-shaped. A burst’s area defines how far from the point of origin the spell’s effect extends.
An emanation spell functions like a burst spell, except that the effect continues to radiate from the point of origin for the duration of the spell. Most emanations are cones or spheres.
A spread spell spreads out like a burst but can turn corners. You select the point of origin, and the spell spreads out a given distance in all directions. Figure the area the spell effect fills by taking into account any turns the spell effect takes.
Cone, Cylinder, Line, or Sphere
Most spells that affect an area have a particular shape, such as a cone, cylinder, line, or sphere.
A cone-shaped spell shoots away from you in a quarter-circle in the direction you designate. It starts from any corner of your square and widens out as it goes. Most cones are either bursts or emanations (see above), and thus won’t go around corners.
When casting a cylinder-shaped spell, you select the spell’s point of origin. This point is the center of a horizontal circle, and the spell shoots down from the circle, filling a cylinder. A cylinder-shaped spell ignores any obstructions within its area.
A line-shaped spell shoots away from you in a line in the direction you designate. It starts from any corner of your square and extends to the limit of its range or until it strikes a barrier that blocks line of effect. A line-shaped spell affects all creatures in squares that the line passes through.
A sphere-shaped spell expands from its point of origin to fill a spherical area. Spheres may be bursts, emanations, or spreads.
Creatures
A spell with this kind of area affects creatures directly (like a targeted spell), but it affects all creatures in an area of some kind rather than individual creatures you select. The area might be a spherical burst, a cone-shaped burst, or some other shape.
Many spells affect "living creatures," which means all creatures other than constructs and undead. Creatures in the spell’s area that are not of the appropriate type do not count against the creatures affected.