One of the greatest things about formians and other planar creatures is just that- they are found on multiple planes. There is little reason to have all formian hives the same, moreso with the contact they have with other races. A hive that is attempting to take a world where there is a xixchil population may very well adapt those insectoids' form of biotechnology where a "nearby" hive in the ethereal plane attempts to enslave a xill population and uses them to move between the ethereal and prime material plane that much easier (and faster). So here are some other ideas on associated species and technology of the formians.

Last year, I asked what sort of technology do formians have over at rpg.net: http://forum.rpg.net/showthread.php?626899-Do-Formians-use-technology and that turned into a rather interesting discusion on their behavior as well as their technology. I am a strong proponent that they are very much like neogi or, even better, the Borg from Stark Trek. Their taskmasters do enslave others but that is just the beginning. This is and is no like ants that enslave other ants, as those animals have to collect larvae every so often to get more workers. It is also similar to the ants who have domesticated other insects (scales, aphids and their kin mostly). So formians breed their slaves to whatever they want as well as going into the "wild" and getting more raw stock. The decendants of their wild slaves become so much a part of the hive that attempts to release them are pointless.

And it can get pretty freaky in how much a creature can be modified. In Perpetrated Press' Arsenal sourcebook, psionic weapons are modified creatures. They sort of remind me of the Skrill from Earth: Final Conflict ( http://en.wikipedia.org/wiki/Taelon#Skrills.2C_living_high_energy_weapons ). If some formian hives learn how to do this to psionic creatures, there is no reason that others may not be able to make their own with magical creatures (straight magic, incarnum or some variant). And then there is the cybernetic implants in PP's Factory book. They could easily be made from metal or living creatures with no impact on game mechanics. But that is a bit extreme, so let's take it back a notch.

Fortunately there are already a few examples of creatures that can be used as slave bred races. The tasked genies from the first Annual Monstrous Compendium are just that- genies that have been bred for specific tasks. Some of them could be replaced with the standard elementals. Either may sound strange, but formians are spread through out the planes, include the elements. Illithids may seem a bit odd, but they are usually found in relatively small numbers, small enough to be overwhelmed by a formian army. In Dragon 150 there are animals from the illithid homeword and they were updated in Lords of Madness. They could easily be used as the results of formians breeding illithids, using different host bodies and magic to turn mindflayers into stupid beasts. Beholders may seem even more powerful but one of them facing a thousand formians will lose. Once a handful is controlled by a hive, they can be bred and the resulting young can be enslaved as well. The result are abominations. They were first (and best) described in the Monstrous Compendium for Spelljammer, found their way into the Monstrous Manual and a few in Lords of Madness. Other beholder kin work as well, but do not have the hive vibe of abomination. And then there are spiders. In one of the MCs for Planescape there is mention that spiders are found on most of the planes of the wheel and I would think they are also fairly common on the elemental planes as well. Dragon issues 67 and 118 have a lot of monstrous spiders, some of which could be bred species. There is no mention of formian larvae so they may very well use spiders to make silk.

And then there are those that need new designs. The four "lesser" giants- hill, stone, frost and fire- are small enough to be affected by a taskmaster and all of them can be useful. Hill and stone giants make useful guards as well as brute strength for digging (especially in numbers). Frost giants, and winter wolves for that matter, are handy when formians invade cold regions. They and fire giants have very different ways of making technology that is useful for themselves and their formian masters. After generations of breeding, hill and stone giants should be larger and less intelligent whereas the others should be smaller and retain their intelligence. It isn't so much the strength of the frost and fire giants that is desirable, but rather their innate abilities to work with metal. A hive with a giant's forge will be obvious, at least on the inside. Some hives may even try to produce hybrids of frost and fire giants, producing many deformed creatures to be culled but occasionally something more than its parents.

If the GM interprets the taskmaster description as it is written, formians can add any creature smaller than Large to their hive no matter the monster type. Zombies and skeletons are taken because they are abundant in some areas and the negative energy they are powered by may be taken for other uses. Oozes can be used to degrade or recycle materials (and there are plenty of examples out there). Vermin are not that popular because they don't do much beyond the existing formian castes. Spiders, as I mentioned, have silk and some other vermin have wings (though so does one caste of formian, in the 3e Fiend Folio) or are amphibious and they go places where formians can not. Plant monsters are not used often either because they can not survive in the hive for very long. Treants may be turned into shrubs with herbal powers in their fruit or leaves, may be combined magically with other plants to give them limited shapeshifting abilities (to spy and scout) or their innate connection to nature may be used in the formians' landscaping projects. Fungal monsters, such as myconids, might be found in most hives on planes where they exist (and even some where they do not, taken there by the formians). They may be turned into molds, hybrids with brown or yellow mold, their spores constantly spread throughout the hive's air supply (of course the formians and the other slaves would be immune).

Demons and celestials may very well be the most common slaves in some hives. Formians invade everywhere sooner or later and see the locals as potential additions to the hive (though the Hungry Little Monsters pdf has monsters resulting from formian eggs layed in the Abyss). They are more likely to succeed in chaotic planes as lawful ones are more organized and usually can repel a formian invasion (if they are discovered in time).

One creature type I am leery of giving formians is dragons, at least true dragons. Yes, they may be enslaved when just out of the egg, but they do grow beyond their taskmaster's ability to control (when they grow to Huge) and dragons are more likely to exterminate formian hives if they get an inkling that the ant-people are attempting to absorb their species into the hive. Other dragons, such as the ambush drake, might be used as powerful guards or trackers.

Formians are potentially the greatest slaving race in D&D, far outstripping neogi, kopru and aboleths. They should be seen as something much scarier than ants. One might not know all the slave species hidden away within hive and may never know if the party is repelled or the formians bring in reinforcements from another plane ...