(3.5) My three minions

[Voice of Reason]

Hmm, so very high-level minions indeed. I truely wish that I could help you out with minion 3, but I don't think of anything I have access to that will help (not to mention that I recently loaned almost all of my 3.5 books to a friend for their game. I'll have a look around nontheless.

EDIT: Well, turns out my Savage Species sourcebook is still lying around, and I found something that may interest you: the Master of Flies prestige class. Now, it's not exactly what you wanted, but it's pretty close.

Prereqs: 5 Escape Artist, 8 Knowledge: nature. Either Alter Form, Change Shape, or Wild Shape. Feat: Quick change (savage species).

This prestige class is exclusively vermin and swarm-oriented, and at level 10, lets you do the following:

-Summon Swarm/Insect Plague, Creeping Doom 10/day as a 10th level sorcerer.

-Swarm Shape. This works exactly like wild shape, exept that you can only assume the form of a swarm in either the Summon Swarm, Insect Plague, or Creeping Doom spells. You can assume a form up to 2 size catergories above yourself. This ability is usable 6/day, and lasts 10 hours each.

-Pied Piper. 1/day, can attempt to charm a number of hit die of vermin up to charecter level within 100'. Will save 14+cha to negate. Failure means vermin follow the Master of Flies for as long as concentration; dangerous areas result in new saving throw.

-Flyblown. Swarm shape as a free action.

-Awaken Vermin. Exactly as the druid spell 1/week as a spell-like ability, exept that it only works on vermin (which means, incidentally, that it is possible to have an awakened swarm )

-Swarm Leap 1/day. Can teleport through swarms. Works like the druid spell Transport Via Plants, exept you enter and exit via swarm, and the distance is unlimited.

Best way to do this would probably to have said minion be a Druid/x Master of Flies/10. Take the feat that allows you to cast while wild-shaped, which will also incidentally let you cast spells in swarm shape. It's not the most optimal use of levels by any stretch of the imagination, but it works nicely as a good, challenging encounter for the PCs. Some of the benefits/suggested tactics:

-Swarm Shape can be done as a free action. Use this liberally, feel free to monologue a bit with this guy, and when somebody tries to interupt you with the anticlimactic "I shoot at him," tell the PC that his arrow has the unintended effect of causing the NPC to burst outward into a swarm of thousands of beetles, which advance on his position

-Locust Swarm or Centipede Swarm shapes are probably the two that I recomend most (one for flying, one for damage). The centipede swarm is particularily nice, as it makes your NPC immune to all weapon damage, gives him darkvision 60', Swarm Traits, and Tremorsense 30'. Keep in mind that you need to restat the swarm as up to 2 size catergories above the NPC's size, as well as change the damage (probably to 4d6 auto instead of the 2d6, see the Swarm Traits subbar for more info) as well as increase the save against the centipedes' poison.

-You can continue to cast spells while Swarm Shaped. It will probably provoke AoO, but the NPC is immune to all weapon damage anyways! Since you aren't using your standard action to attack, use it to throw out some minor healing/damage, or to summon a few more swarms if your one guy isn't enough.

-The Awaken and/or pied piper abilities can be used to drag a few more vermin into this battle. I would recomend things like Monsterous Spiders, Centipedes, and Scorpions so that the PCs without spells will have a useful way to contribute to the battle. (keep in mind that smart PCs may try to lure summoned swarms so that they damage the other vermin; let them have thier fun).

-If the need arises for your NPC minion to make an escape (for example, if he becomes more important to the plot than you anticipated) then escape is only a Swarm Leap away.