Type of Feat: Class
- Rogues gain sneak attack +1d6 at 1st level, and increases by 1d6 every two rogue levels thereafter. At 30th level the final value is +15d6.
- Arcane tricksters gain sneak attack +1d6 at 2nd level, and increases by 1d6 every two arcane trickster levels thereafter. At 10th level the final value is +5d6.
- Assassins gain death attack (not the same as sneak attack for prestige class requirements) +1d6 at 1st level, and increases by 1d6 every two assassin levels thereafter. At 9th level the final value is +5d6.
- Blackguards gain sneak attack +1d6 at 4th level, and increases by 1d6 every third level beyond 4th (7th and 10th). At 10th level the final value is +3d6.
- Invisible Blades gain Bleeding Wound at 1st level, this increases in rank every two additional levels (3rd and 5th). At 5th level the final value is +6 bleeding damage. For the purposes of prestige class requirements, each +2 of bleeding wound damage is the equivalent of +1d6 sneak attack damage.
- Shadow thieves of Amn sneak attack +1d6 at 1st level, and increases by 1d6 every second level (3rd and 5th). At 5th level the final value is +3d6.
- Neverwinter Nine sneak attack +2d6 at 3rd level from Frantic Reactions.
Specifics: Whenever the character makes a successful attack against an opponent who is flat-footed, or cannot see you (i.e., you are in Stealth Mode or invisible) or is actively in combat against another opponent (i.e., flanked), you deal extra damage (initially 1d6). This extra damage is not multiplied in the case of a critical hit. Any creatures that are immune to critical hits, such as constructs and undead, are also immune to sneak attacks. Sneak attack damage from multiple classes always stacks.
How sneak attack works
The extra damage is of the same type as the weapon you hit with (so a longsword deals slashing damage). The weapon you use does not matter (a greatsword is as effective as a dagger). It applies for every single attack that hits (so may include offhand weapons and the like). They are totally automatic and have no penalty to hit.
For ranged attacks to be considered sneak attack there is an additional restriction that the attacker must be within 30 feet (roughly one tile of an interior area).
A normal attack is upgraded to a sneak attack under the following circumstances (for both melee or ranged attacks):
- Flat-Footed - Target is stunned, paralyzed, asleep. Unlike NWN a target who has been knocked down is not automatically subject to sneak attacks.
- No sight of attacker - If the target cannot see the attacker (blindness, invisibility, and stealth might apply for this situation).
- The target is being flanked.
- The target is under the effects of Feint.
- The target is under the effects of Impromptu Sneak Attack.
This means spellcasters who are casting defensive spells, or not attacking the target, can have their concentration broken more easily by sneak attacks.
Defenses against sneak attacks
- Improved Uncanny Dodge - A character with this feat cannot be the victim of sneak attack damage from flanking (sneak attacks from other sources still apply) unless the attacker has 4 or more levels in classes that grant Uncanny Dodge (such as Rogue or Assassin) than the defender has also with class levels that grant Uncanny Dodge.
- Immunity to Sneak attacks. Dragons have a specific immunity to sneak attacks.
- Immunity to Critical Hits. Any creatures who are immune to critical hits are also immune to sneak attacks (note that while this should be true, it doesn't always work and Deathless Mastery is one such). Some creatures have immunity to critical hits (e.g. Elementals, Undead, Constructs) as a racial property. Others can gain it as a class ability (Deathless Mastery), from a spell (Iron Body, Stone Body or Living Undeath), or a spell like ability (Oaken Resilience).
Epic Precision and Critical Immune foes
- Epic precision is very useful for (partially) bypassing an opponent's immunity to sneak attacks or critical hits. Opponents immune to critical hits normally ignore extra damage delivered from sneak attacks, as well as other class-related feats shown below. However if the attacker also has epic precision, damage is as follows:
- Sneak Attack will deliver half damage when used in conjunction with this feat, but additional effects, such as those from Crippling Strike, will not be applied to the target
- Bleeding Wound: will deliver full damage when used in conjunction with this feat
- Death Attack: will deliver full damage when used in conjunction with this feat
- Insightful Strike: will deliver full damage when used in conjunction with this feat. Also, unlike Sneak Attack and Death Attack, Insightful Strike damage is multiplied on critical hits
Sneak attack additional notes
These feats work with, or do a special version of, sneak attack:
- Bleeding Wound - An Invisible Blade gains this modified form of sneak attack at level 1; it increases in rank at the 3rd and 5th level of that class. An opponent who is damaged by sneak attack takes two points of damage per rank of bleeding wound for the next 3 rounds.
- Crippling Strike - A rogue with this ability can sneak attack opponents with such precision that her blows weaken and hamper them. An opponent damaged by one of her sneak attacks also takes 2 points of Strength damage.
- Death Attack - At 1st level, the assassin can make a special sneak attack called a death attack. This ability adds to the rogue's sneak attack ability, adding an extra 1d6 points of damage. This bonus rises to +2d6 at 3rd level, +3d6 at 5th level, +4d6 at 7th level, and +5d6 at 9th level. If used against an opponent not already in combat, a successful Death Attack forces the victim to make a Fortitude save or become paralyzed.
- Epic Precision - This ability allows sneak attack to damage enemies normally immune to critical hits as indicated above.
- Feint - An opponent who falls victim to the Feint feat (opposed check of d20 + Bluff skill versus d20 + BAB + Spot skill) is considered flat-footed for a round and can be sneak attacked.
- Impromptu Sneak Attack - Once per day, a 3rd-level arcane trickster can use this ability to deny an enemy his Dexterity bonus to AC for one round, allowing the target to be sneak attacked. The arcane trickster gains an additional daily use of this ability at 7th level, and again at 9th level.
- NWN did not incorporate non-lethal damage. NWN2 may not include it either for the same reasons.
- Assassins in NWN don't directly gain sneak attack bonus. Instead, the additional damage is incorporated into an altered version of the death attack ability.
- Details on the 3.5e version of this class feat are in the talk page.