Fang of Lolth

Worshippers of Lolth occasionally create a magic item called a fang scarab that gives spiders an attack bonus. Such an item is ordinary enough—until a bard or a rogue makes a successful check to trick it into working for her. Though she does gain the benefit of the fang scarab, it also fuses to her neck, beginning a metamorphosis that could eventually turn her into a half-spider abomination.
Some fight this transformation, continuing their adventuring careers normally with only a few outward manifestations of spiderlike qualities. Others embrace the metamorphosis and earn levels in the Fang of Lolth class, giving over their bodies to the image of the Demon Queen of Spiders. Regardless of their attitudes toward their new legacy, those that have fused with fang scarabs eventually learn that death is the only way to separate the item from their bodies.  Clerics and other agents of Lolth know about this aspect of fang scarabs, so they spare no effort to bring anyone who has fused with one into Lolth’s service. Most NPC fangs of Lolth work for clerics of the Spider Queen, but a few renegades exist who want the power of the spider but a few aren’t willing to bow to Lolth. Agents of the Spider Queen constantly hound such characters. Intent on either bringing them into Lolth’s service or killing to recover the fang scarabs.

Spider Bite

The fang of Lolth can unhinge her jaw and bite with her razor-sharp teeth as an attack action. Her bite is a natural attack that deals 1d6 points of damage if she is Medium-size, or 1d4 points of damage if she is Small. This attack does not provoke an attack of opportunity from the fang of Lolth's foe. 

Bonus Proficiencies

When you choose this archetype at 3rd level, you gain proficiency in the disguise kit and the poisoner’s kit.

Spider-like Movement

Starting at 3rd level, you gain a climb speed of 20 feet.

Spider Vision

At 9th level, the fang of Lolth gains increased visual acuity in the form of advantage on Perception checks in scenarios that rely on sight.  She also gains darkvision.

Natural Armor

At 9th level, the character's skin toughens, granting her a +2 natural armor bonus. At 17th level, the bonus increases to a +4.

Spider Limbs

At 13th level, the fang of Lolth actually grows two more pairs of limbs, which emerge from her back or the sides of her torso when needed and are fully retractable. Extending or retracting the spider limbs is a move-equivalent action that does not provoke attacks of opportunity. The fang of Lolth's spider legs are tipped with simple claws that can hold weapons and other items normally, though they are incapable of the fine manipulation required for spellcasting or using Dexterity-based skills such as Open Lock and Pick Pocket. Despite her extra limbs, the fang of Lolth is still limited to one standard action per round. She can, however, make a secondary natural attack with each clawed spider leg at the standard penalty of not adding ability modifiers to the damage. Her claws deal ld4 points of damage if she is Medium-size or 1d3 points of damage if she is Small. The fang of Lolth's spider limbs grow long and sturdy enough to propel her forward, if she devotes two of her spider legs entirely to locomotion, her land and climb speeds each increase by 20 feet.

Vermin Type

At 17th level, the fang of Lolth's creature type changes to vermin, though she retains her previous Intelligence score, Hit Die type, and abilities. As a vermin, she becomes immune to mind-influencing effects (charms, compulsions, phantasms, patterns, and morale effects).

Physical Changes

Every few levels the fang of Lolth's body undergoes a metamorphosis.  With the exception of the unhinged jaw and the extra spider limbs (both of which allow special attacks as detailed above), all these changes are merely cosmetic, but they are permanent. These spiderlike features do not alter the fang of Lolth's Charisma score or interpersonal skills, but the DM may choose to impose a circumstance penalty on any checks involving interaction with creatures that find such changes frightening. A clever fang of Lolth may avoid this issue by wearing a hat of disguise or employing some other magic that alters her appearance.