Chosen One (CR 2)

Medium Monstrous Humanoid
Alignment: Always chaotic evil
Initiative: +1 (Dex); Senses: darkvision 60 ft., Listen +5, and Spot +5

AC: 13 (+1 Dex, +2 natural), touch 11, flat-footed 12
Hit Dice: 3d8 (13 hp)
Fort +1, Ref +4, Will +4
Speed: 30 ft.
Space: 5 ft./5 ft.
Base Attack +3; Grapple +3
Attack: 2 claws +3 melee; bite +1 melee
Full Attack: 2 claws +3 melee; bite +1 melee
Damage: Claw 1d4; bite 1d8 plus poison
Special Attacks/Actions: Poison
Abilities: Str 11, Dex 13, Con 11, Int 6, Wis 12, Cha 10
Special Qualities:
Feats: Alertness; Multiattack
Skills: Climb +2, Listen +5, and Spot +5
Advancement: -
Climate/Terrain: Any land
Organization: Solitary, gang (3-8), band (9-20), or plague (21-40)
Treasure/Possessions: None

Source: Monster Compendium: Monsters of Faerûn

Poison (Ex): Those hit by a chosen one's bite attack must succeed at a Fortitude save (DC 11) or be injected with poison. The initial damage is 1d4 points of temporary Constitution damage and the secondary damage is 2d4 points of temporary Constitution damage.

Chosen ones attack fearlessly, biting with fangs and slashing with filthy claws. They obey their creators' commands to the best of their ability. However, a chosen one occasionally goes berserk, somehow recovering some memory of its past life and the tortures it endured at its master's hand. For each consecutive round a chosen one is in combat after the fifth, there is a cumulative 1% chance that it goes berserk, screaming horribly and fleeing combat in search of its creator.