Here's one that I modified/balanced a bit to better suit BG:
Thrall of Malcanthet====Description====
Malcanthet often refers to her thralls almost lovingly as her favored children. These are mortal hedonists and seducers who have given their entire lives over to the fulfillment of pleasure and pain. Only when working to subvert the values and morals of the innocent do they turn from this consuming need and it is said that each emotional and physical climax achieved by these thralls is felt in turn by their lascivious mistress deep in Shendilavri.
Thralls of Malcanthet often lead her cults on the Material Plane, but just as often work in secret in the employ of dockside brothels or in the harems of powerful kings. Malcanthet allows only women to become her thralls, for only they can properly transmit the particular thrills and rewards the Queen of Succubi seeks to harvest from the Material Plane.
====Requirements====
Skills: Bluff 9, Diplomacy 9, Perform 6
Feats: Thrall To Demon, Spell Focus (Enchantment), Negotiator
Spellcasting: Able to cast 3rd-level arcane spells, or Lesser Invocations
Alignment Required: Chaotic Evil
Gender Required: Female
====Class features progression====
Class Hit die=d8
Proficiencies= Exotic (Whip)
Skill Points= 6 + Int Modifier
Class Skills= Appraise, Concentration, Diplomacy, Disguise, Gather Information, Intimidate, Lore: Arcana, Lore: The Planes, Listen, Perform, Sense Motive, Spellcraft, Spot
BAB=Low
Saves= High Will, High Reflex, High Fortitude
====Additional progressions====
- Abyssal Power
- Thoughts of the Mindless
- Profane Beauty
- Scion of Lust
Invocations/Spellcasting Progression
At each level, you gain new invocations/spells known and an increase in invoker/spellcaster level as if you had also gained a level in the invoker/spellcaster class. You do not, however, gain any other benefit a character of that class would have gained.
Abyssal Power
The mighty power of the Abyss flows through a Thrall of Malcanthet. At 1st, 3rd and 5th levels spells that belong to the School of Enchantment have their spellpower increased by one. Mind-Affecting Invocations have their CL increased by 3 and DC by 1 instead.
Thoughts of the Mindless
At 2nd level, a Thrall of Malcanthet gains some of her mistress' ability to seduce or enchant even those that would normally make this impossible. They can treat any of the following immunities on any creature whose CR or Character Level is lower than theirs as a +4 bonus on the relevant save instead: charms, compulsions, fear effects, enchantments and mind-affecting effects.
Profane Beauty
At 3rd level, as long as a Thrall of Malcanthet wears no armor and wields no shield, she gains a deflection bonus to her armor class equal to half her Charisma bonus, to a maximum bonus equal to her Thrall class level.
Scion of Lust
At 5th level, a Thrall of Malcanthet gains a close connection to the powers of lust. She permanently gains 2 points of Charisma