From Compendium of Worldly Lore
Most creatures view creepy, crawly insects with revulsion. To a vermin keeper, however, they’re perfect killers—creatures whose supreme adaptations to their environs inspire a sense of awe. Vermin keepers come almost exclusively from the ranks of druids. Some are upperworlders whose eyes have been opened to the beauty of bugs; others loved bugs to begin with and merely learned the druidic arts so that they could apply them to insects. Most characters who care enough about vermin to take levels in the vermin keeper prestige class pursue it to the exclusion of all else.
Interestingly, not every character who pursues this prestige class actually loves bugs. Sometimes a person who particularly hates or fears insects or spiders decides to study them in order to understand or overmaster them.
Role: Spell Utility
Characteristics: Druidic folk who have mastered the art of influencing and shaping into vermin
Source: Underdark
Game Rule Information
The Vermin Keeper has the following game statistics.
Abilities: Wisdom for casting, Charisma for influencing the Vermin, and having a high Constitution for keeping you and your vermin friends in the fight
Alignment: Any
Hit Die: d8
Starting Gold: N/A
Class Skills
The Vermin Keeper's class skills are Concentration (Con), Craft (any) (Int), Handle Animal (Cha), Heal (Wis), Knowledge (nature) (Int), Knowledge (Underdark local) (Int), Listen (Wis), Profession (Wis), Search (Int), Spellcraft (Int), Spot (Wis), Swim (Str), and Wilderness Lore (Wis)..
Skill Points at 1st Level: (4 + Int modifier) × 4
Skill Points at Each Additional Level: 4 + Int modifier
Class Features
All of the following are class features of the Vermin Keeper.
Weapon and Armor Proficiency: A Vermin Keeper is proficient with whatever they were already proficient with prior to taking levels in this class.
Spells per Day: At each vermin keeper level, the character gains new spells per day (and spells known, if applicable) as if he had also gained a level in a spellcasting class to which he belonged before adding the prestige class level. He does not, however, gain any other benefit a character of that class would have gained (improved chance of turning or rebuking undead, metamagic or item creation feats, and the like). If the character had more than one spellcasting class before becoming a vermin keeper, the player must decide to which class to add each vermin keeper level for the purpose of determining spells per day, spells known, and overall caster level.
Handle Vermin Ex: At 1st level, a vermin keeper can apply his Handle Animal skill to vermin.
Vermin Empathy Ex: A vermin keeper can apply his wild empathy class ability to vermin. Vermin begin with an unfriendly attitude.
Vermin Form Su: Beginning at 1st level, a vermin keeper can use his wild shape ability to assume a vermin form. Starting at 1st level, he can turn himself into any small vermin. As he gains vermin keeper levels, the diversity of forms available to him increases. He can become a tiny vermin at 2nd level, a medium vermin at 4th level, a diminutive vermin at 5th level, a large vermin at 7th level, a Fine vermin at 8th level, and a huge vermin at 9th level.
Venom Immunity Ex: At 3rd level, a vermin keeper gains immunity to all organic poisons. This category includes all monster poisons but not mineral poisons or poison gas.
Vermin Companion Ex: At 3rd level, a vermin keeper can call a small, medium, or large vermin as a companion in lieu of an animal (see sidebar for details). He may choose any kind of vermin for which statistics are provided in the Monster Manual. A vermin keeper cannot retain the animal companion he had from his previous class (if any) after he calls a vermin companion. Except as noted in the sidebar, this ability works the same as a druid's animal companion ability.
Extra Wild Shape Feat: A vermin keeper gains Extra Wild Shape as a bonus feat at 4th and 6th levels.
Swarm Form Su: At 10th level, a vermin keeper can use his wild shape to assume the form of any vermin swarm (any swarm whose constituent creatures are of the vermin type).