A shadow priest must select the Darkness domain or the Loss or Night subdomain. The shadow priest does not get a second domain. In all other respects, this works like and replaces the standard cleric’s domain ability.
A shadow priest adds the following spells to her spell list:
At 1st level, a shadow priest, rather than channeling positive or negative energy, instead channels the power of eternal darkness. This ability is similar to channeling negative energy, but instead of healing undead and dealing damage to living creatures, this blast of shadowy power can only harm creatures and create darkness.
Channeling darkness causes a burst that affects all creatures in a 30-foot radius centered on the shadow priest. Living creatures take 1d4 points of damage, increasing by 1d4 at every two levels beyond 1st (to a maximum of 10d4 at 19th level). Undead creatures are not healed by this energy, but are instead staggered for 1 round by the overwhelming power. Creatures in the burst receive a Will saving throw to negate the effects.
Instead of harming creatures with this energy, a shadow priest can instead use channel darkness to snuff out light sources within the burst. Non-magical light sources such as torches, lanterns, or sunrods are automatically extinguished (as a dust of twilightAPG spell). Any 0th level spell with the light descriptor in the area is dispelled (as dispel magic). The level of light spells that can be dispelled with channel darkness increases by 1 for every two levels beyond first, up to being able to dispel 9th level or lower light spells at 19th level. Whether the magical effects are dispelled or not, the illumination level in the area drops by 1 step, as the spell darkness, for 1 minute. At 10th level, the light level drops by 2 steps. At 15th level, it drops by 3 steps, and areas of dim light or darkness become supernaturally dark (even creatures with darkvision cannot see within it). The shadows created by channel darkness is treated as a darkness spell equal to the level of light spell it can dispel (0th at 1st level, increasing by 1 level for every two shadow priest levels after 1st).
A shadow priest may channel darkness a number of times per day equal to 3 + her Charisma modifier. Doing so is a standard action that does not provoke attacks of opportunity. A shadow priest must present her symbol to use this ability.
For the purposes of feats that affect channel energy, this ability counts as channeling negative energy. If the feat changes the way the shadow priest channels or deals damage with her channeling, use the amount of damage this ability harms living creatures to determine the damage-dealing potential of the affected ability. For instance, if a 5th-level shadow priest takes the Channel Smite feat, her channeling deals an additional 3d4 points of damage to living creatures on a successful hit (though they may save to negate the damage). This ability replaces channel energy.
At 8th level, whenever a shadow priest casts a spell when she is in dim light or darkness, the spell takes effect at +1 caster level. In addition, if the shadow priest prepares a spell with the darkness or shadow descriptor or of the shadow subschool that has one or more metamagic feats applied, she reduces the total level adjustment to the spell by 1 (minimum 0).