Dark Stalker (CR 4)

Medium Humanoid
Alignment: Usually chaotic neutral
Initiative: +7 (+3 Dex, +4 Improved Initiative); Senses: blindsight 60 ft., Listen +5, and Spot +5

AC: 17 (+3 Dex, +2 leather armor, +2 natural) touch 13, flat-footed 14
Hit Dice: 3d8+3 (16 hp)
Fort +2, Ref +8, Will +3
Speed: 30 ft.
Space: 5 ft./5 ft.
Base Attack +2; Grapple +4
Attack: Short sword +4 melee, or javelin +3 ranged
Full Attack: Short sword +4 melee, or javelin +5 ranged
Damage: Short sword 1d6+2 plus poison, javelin 1d6+2 plus poison
Special Attacks/Actions: Fog cloud, poison use, shadow cloak, sneak attack +3d6
Abilities: Str 14, Dex 17, Con 13, Int 13, Wis 14, Cha 16
Special Qualities: light sensitivity
Feats: Improved Initiative; Lightning Reflexes
Skills: Hide +6*, Listen +5, Move Silently +6*, Sleight of Hand +6, Spot +5, and Tumble +6
Advancement: By character class
Climate/Terrain: Any underground
Organization: Solitary, band (1 plus 2-5 dark creepers), or tribe (2-5 plus 20-80 dark creepers)
Treasure/Possessions: Standard

Source: Fiend Folio

Fog Cloud (Sp): Twice per day, a dark stalker can use fog cloud as the spell cast by a 5th-level sorcerer.

Poison Use (Ex): Dark stalkers never risk accidentally poisoning themselves when applying poison to a blade. They typically use shadow essence poison (Fort DC 17, initial damage 1 point of Strength drain, secondary damage 2d6 points of Strength damage) on both their swords and their javelins. A dark stalker usually enters combat with its blade and four javelins coated with poison.

Shadow Cloak (Su): Three times per day, a dark one can wrap itself in a cloak of shadows that grants it concealment from its foes. In shadows or darkness, the shadow cloak gives the creature nine-tenths concealment (40% miss chance for attackers). In bright light, the shadow cloak provides only one-half concealment (20% miss chance). Darkvision does not negate the dark one's concealment, since the shadow cloak is formed from magical darkness. Creatures that can see in magical darkness, such as devils, do not have a miss chance when striking a dark one.

Sneak Attack (Ex): Anytime a dark one's target is denied a Dexterity bonus, or when a target is flanked by a dark one, the dark one deals additional damage on a successful melee attack. Dark creepers deal an additional 2d6 points of damage, and dark stalkers deal an additional 3d6 points of damage.

Blindsight (Ex): A dark one maneuvers and fights not only by sight, but also by using hearing and smell to ascertain its surroundings. This ability enables it to discern objects and creatures within 60 feet. A dark one usually does not need to make Spot or Listen checks to notice creatures within range of its blindsight.

Light Sensitivity (Ex): When exposed to sunlight, or to light equivalent to a daylight spell, a dark one takes a -2 morale penalty on all attacks, saves, checks, and damage rolls.

Skills: When in shadowy areas, a dark one has a +8 racial bonus on Hide checks and a +4 racial bonus on Move Silently checks.

Dark ones are extremely stealthy, but cowardly. They prefer to fight under the cover of complete darkness and flee when the odds turn against them. They are masters of ambush and often pick off individuals from the shadows.

Dark stalkers lead dark creepers into battle, and they place poison on their short swords to deal terrible wounds. They use fog cloud to escape from powerful opponents.