Kopru (CR 6)
Medium Monstrous Humanoid (Aquatic)
Alignment: Always chaotic evil
Initiative: +2 (Dex); Senses: darkvision 60 ft.
AC: 15 (+2 Dex, +3 natural), touch 12, flat-footed 13
Hit Dice: 8d8 (36 hp)
Fort +2, Ref +8, Will +9
Speed: 5 ft., swim 40 ft.
Space: 5 ft./5 ft.
Base Attack +8; Grapple +10
Attack: Tail slap +10 melee and 2 claws +8 melee and bite +8 melee
Full Attack: Tail slap +10 melee and 2 claws +8 melee and bite +8 melee
Damage: Tail slap 1d6+2, claw 1d4+1, bite 1d4+1
Special Attacks: Constrict 3d6+3, dominate person, improved grab
Abilities: Str 15, Dex 14, Con 11, Int 11, Wis 12, Cha 10
Special Qualities:
Feats: Iron Will; Multiattack; Skill Focus (Escape Artist)
Skills: Concentration +8, Escape Artist +11, Move Silently +6, Search +4, and Swim +10
Advancement: 9-10 HD (Medium-size); 11-12 HD (Large)
Climate/Terrain: Warm aquatic and marsh
Organization: Solitary, pair, patrol (3-5), or colony (6-24)
Treasure/Possessions: Standard coins (gold and platinum only), standard goods (gems only), no items
Source:
Monster Manual II
Many generations ago, the koprus built a large and mysterious civilization under the sea. For unknown reasons their society declined, becoming ever more decrepit and degenerate, until now almost none of its former glory remains.
A kopru resembles no known creature, but it combines several familiar features into one monstrous whole. Its is vaguely eel-like but ends in three long, flexible, barbed tails. Its chest is nearly human, and the hands on its two arms end in vicious webbed claws. Its head grows directly from its trunk, like a fish's, and has large, unblinking eyes. The mouth is surrounded by four tentacles - an oddity that has led some scholars to propose that the koprus may somehow be related to mind flayers.
Koprus speak Common and Aquan.
Combat
Out of the water, a kopru is nearly helpless. On land, it cannot attack with its claws because it needs its arms to drag itself across the ground or prop its body up. A kopru in water, however, is a ferocious opponent in melee combat. Along with its claws and teeth, it lashes out with its tails, all three of which strike as one.
Constrict (Ex): With a successful grapple check, a kopru can constrict a grabbed opponent, dealing 3d6+3 points of bludgeoning damage.
Dominate Person (Su): Once per day, a kopru can produce an effect like that of a dominate person spell (caster 10th; Will save DC 14), except that the range is 180 feet and the duration is eight days.
Improved Grab (Ex): If a kopru hits an opponent that is its own size or smaller with a tail attack, it deals normal damage and attempts to start a grapple as a free action without provoking an attack of opportunity (grapple bonus +17, including a +7 racial bonus on grapple checks). If it gets a hold, it also constricts in the same round. Thereafter, the kopru has the option to conduct the grapple normally, or simply use its tail to hold the opponent (-20 penalty on grapple check, but the kopru is not considered grappled). In either case, each successful grapple check it makes during successive rounds automatically deals tail and constrict damage.
KOPRU SOCIETY
Kopru society is matriarchal and savage. The monsters live in underwater caves, often near the sites of their ancient ruined cities. But these reminders of their former glory only serve to increase their bitterness.