Sahuagin are vicious and cruel, but very cunning. Their lieutenants even more so.

Male Sahuagin Ranger 3 (CR 4)

Medium Monstrous Humanoid (Aquatic)
Init +4; Senses Blindsense (30 feet), Darkvision (60 feet); Perception +8

AC 21, touch 14, flat-footed 17 (+2 armor - Sharkskin Leather, +4 Dex, +5 natural)
hp 42 (5d10+15)
Fort +8, Ref +10, Will +6
Weakness Light Blindness

Speed 30 ft., Swimming (60 feet)
Melee Bite (Sahuagin) +8 (1d4+3) and Claw x2 (Sahuagin) +8 x2 (1d4+3) or Masterwork Trident +10 (1d8+3)
Ranged +1 Crossbow, Heavy +6 (1d10+1)
Ranger Spells Known (CL 0, 8 melee touch, 9 ranged touch):

Str 16, Dex 18, Con 16, Int 15, Wis 14, Cha 11
Base Atk +5; CMB +9; CMD 22
Feats Agile Maneuvers, Endurance, Great Fortitude, Point Blank Shot, Weapon Focus: Trident
Skills Appraise +5, Bluff +3, Escape Artist +7, Handle Animal +8, Intimidate +6, Perception +8, Ride +12, Sense Motive +4, Stealth +9, Survival +10, Swim +19
Languages Aquan, Common; Speak with Sharks
SQ Archery Combat Style (Ex), Blood Frenzy (1/day) (Ex), Enemies: Humanoids (Human) (+2 bonus) (Ex), Terrains: Water (+2 bonus) (Ex), Track +1, Wild Empathy +3 (Ex)
Combat Gear Masterwork Trident, Sharkskin Leather, +1 Crossbow, Heavy; Other Gear Potion of Barkskin +4, Potion of Cure Moderate Wounds, Potion of Haste

Agile Maneuvers Use DEX instead of STR for CMB
Archery Combat Style (Ex) Allows the ranger to pick from a variety of archery-related combat style bonus feats.
Blindsense (30 feet) (Ex) Sense things and creatures without seeing them.
Blood Frenzy (1/day) (Ex) Once per day, a sahuagin that takes damage in combat can fly into a frenzy in the following round. It gains +2 Constitution and +2 Strength, but takes a -2 penalty to its AC. The frenzy lasts as long as the battle or 1 minute, whichever is shorter.
Darkvision (60 feet) You can see in the dark (black and white vision only).
Endurance +4 to a variety of skill checks. Sleep in L/M armor with no fatigue.
Enemies: Humanoids (Human) (+2 bonus) (Ex) +2 to rolls vs Humanoids (Human).
Light Blindness (Ex) Blinded for 1r in bright light, dazzled as long as they remain in it.
Point Blank Shot +1 to attack and damage rolls with ranged weapons at up to 30 feet.
Speak with Sharks (Su) A sahuagin can communicate telepathically with sharks to a distance of 150 feet. This communication is limited to simple concepts, such as 'come here,' 'defend me,' or 'attack this target.'
Swimming (60 feet) You have a Swim speed.
Terrains: Water (+2 bonus) (Ex) +2 to rolls vs Water.
Track +1 +1 to survival checks to track.
Wild Empathy +3 (Ex) Improve the atttitude of an animal, as if using Diplomacy.