Canonically speaking, the Night Mask Deathbringers are a special assassination faction of the Night Masks, who more or less do their dirty work. However, in Faerun, it is possible for your character to take on this prestige class without actually being a member of the Night Masks. Once you take on this class, your character immediately becomes a half undead regardless of their previous race.
Night Mask Deathbringers may be of any "evil" alignment.
As they increase in level, Night Mask deathbringers gain more of the powers their undead masters possess, increasing their deadliness and skill.
Creature of Darkness: Animals can sense the death in you, causing them to fear your presence. As a result, all animals except for bats, rats, and wolves have their initial attitudes moved down one category when you first approach them. In addition, you take a –2 penalty on all Ride checks due to the beast’s inherent nervousness at your presence.
Hesitating Stare: Deathbringers can force their opponents to confront their own mortality with but a glance. This ability can be activated once per day at any time, even when you are surprised. You cast a glance at any foe within 30 feet, who must then make a successful Will save (DC 10 + 1/2 your class level + Cha modifier) or be stunned for 1 round. You can use this ability twice per day at 4th level and higher, three times per day at 7th level and higher, and four times per day at 10th level.
Light Sensivity: In sunlight or bright magical light (such as a daylight spell), a deathbringer is dazzled.
Spider Climb: Starting at 1st level, you can act as if you were under the influence of a spider climb spell (caster level equals your deathbringer class level). You can use this ability a number of times per day equal to your Charisma modifier, minimum one.
Feral Senses: At 2nd level, you gain low-light vision—the ability to see twice as far as a human in starlight, moonlight, torchlight, or similar conditions of poor illumination. You retain the ability to distinguish color and detail under these conditions. At 7th level, you gain darkvision out to 60 feet.
Speak with Creatures of the Night: When you reach 3rd level, you can speak with rats, bats, and wolves as if you were under the influence of a speak with animals spell. This ability does nothing to affect the attitude of such creatures.
Ghost Step: Once per day starting at 3rd level, you can make yourself invisible for 1 round. This is a swift action (something you can do as a free action once per round) that does not provoke attacks of opportunity. You can use this ability twice per day at 6th level and higher, and three times per day at 9th level and higher.
Lesser Blood Bond: One of the deathbringer’s most insidious powers, this ability helps you break down the will of her enemies. To use this ability, a deathbringer of 4th level or higher must get the target to drink three drops of her blood. She can do this by hiding the blood in food or drink, or by pinning the target for 1 round and bleeding directly into his mouth.
Once this condition has been fulfilled, the deathbringer can cause a charm person effect to come over the target by speaking directly to him. The words used are unimportant, only that the deathbringer wills the target to be friendly to him. The caster level of the effect equals the deathbringer’s class level, and the DC to resist the effect equals 10 + the deathbringer’s class level + Cha modifier. You can have a number of outstanding blood bonds, active or not, equal to your Charisma modifier. Should you exceed this limit, the oldest blood bond becomes inactive.
Sneak Attack: At 4th level and higher, you deal extra damage when you catch a foe flat-footed or flank a foe, as the rogue class feature described on page 50 of the Player’s Handbook. Sneak-attack dice attained from multiple sources stack.
Improved Evasion: At 5th level, your pseudo-vampiric celerity grants you supernatural reflexes. You now take no damage on a successful Reflex saving throw against area attacks and half damage on a failed save. You do not gain the benefit of this ability if you are helpless.
Slippery Mind: When you attain 6th level, your mind is only partly mortal, allowing you to shrug off mental attacks and compulsions more easily than others. Any time you are affected by an enchantment spell or effect and you fail your saving throw, you can attempt the save again 1 round later at the same DC. You only get one extra chance to succeed per effect.
Greater Blood Bond: This ability, acquired at 10th level, works just like lesser blood bond, except the target comes under the influence of a dominate person spell rather than charm person. A deathbringer can have a number of outstanding blood bonds, active or not, equal to her Charisma modifier. Should she exceed this limit, the oldest blood bond becomes inactive.