(from a tech perspective, magical and psychic perspectives will be added as knowledge is obtained)

A human:
Any type: Simple. If you're a Pred, eat them!

Human military forces:
A Storm Sprite can disable all electronic weapons - mechs, fighters, etc.


Centaurs:
Any type: Tactically speaking: this is fairly simple, if you're tech inclined: a head shot with an explosive shell. The bigger the 'taur the bigger the shell needed. AGM Hellfire, RPGs, etc. would also work.

more later as research continues...

Human: Scout groups out ahead of time, Isolate, utilize fear to your advantage, choose an open surrounding when you strike. You want to know which is the weak link, who you can catch, make sure there's no where to run, etc.

Storm Sprite: Use specialist troops (Psykers, Mages, etc), or long ranged weapons that will be unaffected in the long run (Railguns at long distances, bombs with very large blast radius'). Melee is highly discouraged unless using Magic-Powered Golems of large stature.

Centaur: Like you stated, any really works provided it does the proper damage. Spamming high-calibre / armor piercing rounds towards vitals, explosives, each works fine.

Harpy: Anything that can 'clip' the wings effectively. The lighter build also makes the Harpies less resistant to KE-stlye attacks, and more prone to breaks. Masses of Ballista, Stonethrowers, Ordinance, Anti-Air, or anything that can really fill a large volume of space upwards works well here.

Dryad: Long-Ranged Incendiary Attacks. Napalm Strikes work decently as well, or heavily armored (Or even armoured) personelle using flame weapons. Failing this, poison their water source.

Naga: While open terrain gives you nowhere to run if the Naga catches you, it leaves you also with a large distance to blast the Naga while it recieves no cover. Any pitched force here could potentially drop multiple Naga's before combat is reached, depending on how well dug-in the forces are. Masses of Tanks work decently as well due to excessive range, firepower, and defense. Minefields work nice as well if you don't plan on leaving any time soon, and the Naga's are unaware.

Dridder: If underground: Torch everything in the path. You'll ruin the webs, be able to get anything hidden in deep crevices, etc. High-intensity flames work best here, at least blue hot (Preferably hotter, even up to white if you want to be cruel). Fire is your best bet, beyond flooding the underground system (Which would almost always be too cost inefficient to use often).

If above-ground: Find something to ruin the legs. Drop the legs, it's motionless. Similarly, placing traps that can effect the underbellies can also work to your advantage (Mines, for instance). Worse comes to worse, pit traps and poisoned food can be used in a pinch.

Mermaid: Toxify the water. Failing this, plant large numbers of underwater mines and attack craft with heavy explosive payloads. Not that many counters beyond such, beyond draining the body of water and leaving them out to dry.

Faerie: Take out the wings, as with Harpies. Volume filling is more important here due to size changing, and heavier payloads are recommended to get past any magical resistance. Pet mages or Psykers to weaken their resistances or slow them down (Whether physically or reactionally) are preferred.

2nd generation Military Forces

Utilize the surroundings and combine magic attacks, such as casting fire and then thunder. Engage traps and separate them when in groups. Storm Sprites are advised to stay as far away as possible, unless they know other types of magic.

Storm Sprites

(second strategy) Utilize second generation military artillery or summon the aid of a predator. De-wing the opponent and then close in for a final attack.

Power Suits

(For predators) Crack them open like walnuts and enjoy the human filling.

Nekos

You need a strategy to beat a neko? What kind of predator are you?!

1st generation mechs

Use storm srites. EMP is very effective.

2nd generation mechs

As EMP is now deemed useless, get them over water and drag them under, where their weapons are drastically reduced. Utilize any offensive magic as deemed necessary. Be wary of their lightning speed and avoid any particles they emit.

Arthronodes

At predator level threat during thunder storms. Keep it from water and e;ectricity, and utilize earth magic to crush their shells and metal spikes. Water, fire and especially thunder magic are deemed ineffective versus them.

Everything: Death Star, even to itself.

I thought the guardians would just taunt the Death Star by throwing a ball of energy into the exhaust port, blowing it up automatically and saving them the trouble.

Seriously, what were they thinking? a Steel grate would've helped.

Note to all visitors to Felarya: These ideas are to be freely passed around to all citizens and are open for modification.

April 3, 2008, from the President's desk: It occurs t me that there is considerable ambiguity as to when the Guardians of this world might respond to a major global threat involving the food chain. Namely, removing the giant Predators from the world as a threat to us humans, human sized elves and nekos.

After careful deliberation, a fairly fool proof solution has been found to circumvent the Guardians while also bringing a swift end to the Predators: mass starvation.

The solution: airlift all humans, nekos and elves through the Great Dimensional Gate by Ur-Sagol, all at once if possible, to a designated safe zone outside Felarya (we're still working on this). All cities and villages would be simultaneously evacuated, and swiftly, with the help of the Miratans and other technologically savvy colonies/cities. Intelligence suggests that the Guardians would probably do nothing at all about humans evacuating the planet peacefully, and if the Powers that Be remain silent (or they make up a false story) about the reasons behind the evacuation, it may not even occur to them why it is happening. Still, the faster the evacuation happens, the better: it is likely that once the humans are beyond the Gate into another dimension, the Guardians and Giant Predators cannot reach them - or, at least, the enemy will be out of their element and highly vulnerable. Plus the Gate makes a great choking point: anything hostile coming through can be ambushed.

Sticking points: logistics. The aid of the Miratans would be highly necessary for the success of this operation. They may need someone who is a really good salesman-type to convince them that with the Giant Predators starved to death, they can return and gather as much food as they want to end their famine.

April 3, 2008:

Having made a few deals with the Zentraedi, we have spent a great deal of money purchasing the technology for making Zentraedi macronization chambers.

Here is how these devices work: they are a two way glass techno-cocoon designed to convert normal sized (micronized) humans into 50/60 foot giants, or giants into normal sized humans.

Many Giant Predators of Felarya simply cannot eat 50 foot giant humans. In fact, a Zentraedi physically stands taller than most Giant Naga unless said naga is standing on the tip of its tail. Martial arts training would make such a giant especially lethal to Nagas and many species of Giant Faery, and even the Dryads.

The Zentraedi in full giant form are utterly repulsed at the idea of eating humans or any other moving sentient thing, but the problem of acquiring their macro chambers centered around their knowledge that humans have the capacity to become downright crazy: meaning, somewhere out there, a few humans, once converted to giants, may become like a Giant Predator and feed on other small denizens: namely, elves, nekos... and normal sized humans. The Zentraedi were loathe to sell this technology to us because they are well known among the multi-universe community of humanoid giants and humans coming out of macro chambers and eating other humanoids could greatly soil the Zentraedi reputation. There's not too many things they would despise more than being unfairly tagged with that kind of reputation. Numerous implied threats of going to war over such a situation have delayed our mass deployment of these macro chambers.

The few humans who have been Giant-sized - a single black-ops squad test-patrolling Drider territory - are currently bio-tracked and constantly monitored, The Miratans are not appearing to be currently interested in test-deploying this technology.

April 3, 2008:

It may prove beneficial to study the Opal Mingo's DNA. These creatures are utterly LETHAL to fairies. If this includes Crimson Maidens then this creature becomes of absolutely critical importance in a human city's defense strategy.

Fairies:
Aircraft with AIM-120 Sidewinders are suggested. Flak guns for ground defenses, and Fairy-DNA-seeking explosive drones are the most fun. Find a way to auto-attach one to a fairy's back surreptitiously and wait until she's with a group. Then BOOM.

Also consider making sure your aircraft has thrust vector technology to outmaneuver fairies; you're going to double your kill ratio by mastering the Pugashev Cobra and especially the J-Turn (Herbst maneuver). 5th generation fighters like the F-22 Raptor swooping down from high altitude could be a nightmare for fairies.


Crimson Maidens:
Freeze them, if you can. Nitrogen bombs, or flame retardant foam, might also work. Best to drop fuel-air explosives (FAE) on their magical defense towers. Or on them, period. Decimate whole Fire legions with railgun troops. A surprise attack, en masse, with Mammoth MK-III's, complete with B-2 bomber air support and long range railgun sniper support on the ground, could make for a fairly brief war.

The best offense against all Felaryan preds is simple: Exploding nekos.

-Tomotogami-

For Humans or Nekos: DO NOT let them corner you or out number you, if this happens then you're SOL. Their weakness is rather simple though, Tomotogami's hate the cold (like most dryads). So if you have some sort of freezing weapon or device use it and they'll either stay away from you or die. Otherwise use any weapons you have that are capable of peircing their rubbery hides, be warned they are known to take a lick and keep on kickin' so this will require some tenacity on your part if your to get through this without getting torn apart.

For Predators (they CAN be that dangerous, read their database): Same as above, but if you do find yourself out numbered try to Isolate them, they only attack together if they are after one common goal. If you seperate them the others will move along leaving you with either one or 2 to deal with. However even after you do this the initial fight will still be rather taxing, and will ultimately rely on your strength as a predator to come out victorious, good luck. However if you're skilled in Ice magic, freeze the mofos and keep on your way.

The Predator aspect of combined arms can produce fairly spectacular results against human/neko/elf defense forces, or at least greatly improve their chances of survival against a well organized military "prey" assault.

First, it should be noted that the most central and critical aspect of Predator Combined Arms, is the presence and cooperation of Crimson Maiden Fire Legions for both air and ground "Marines/Special Forces" support. Arguably the most powerful Predator fighting force in Felarya, the Fire Legions themselves can battle large opposing forces, perhaps even masses of technologically advanced enemies.

There are also the Scarlet Elves. Being giant and also highly agile, they can potentially rival Crimson Maidens in that they can strike rapidly, repeatedly, and without much warning. Despite their lack of proficiency in magic, in a combined arms scenario, these creatures are certainly to be woefully underrated, especially against massed forces of giant mecha and main battle tanks/supertanks.

To support the Scarlet Elves and Crimson Maiden Fire Legions, Dryads can serve as a vast, forest-wide communications network; they can also decimate ground forces and, in the event of an incoming napalm attack, call in...

Canopy faeries. Aside from fulfilling basic air and ground combat roles, these forces are phenomenally effective in penetrating enemy lines a la commando forces, and inflicting mass casualties - or taking out human/neko/elf pilots of critical units - with their "belly warp" attack. Upon the onset of this attack, it is highly likely that surrounding forces will be extremely demoralized, especially considering that they cannot hit this target once it starts phasing through dimensions. At the same time, they can be accompanied by...

Storm Sprites as specialists and saboteurs. These beings can utterly decimate electronic systems - and troops as well.

Harpies can distract air units until Faeries of various types can join the fight. Harpies are best utilized on a first-to-fight, first-to-die basis; although Demon harpies can serve as armored air cavalry. Harpies are good at spotting enemy commando units sneaking up on Predator forces by air or land.

Centaurs can run down fleeing ground units but are not advised to charge armored, heavily armed forces. They can serve as fast infantry, charging in to cause confusion and break up enemy ranks. They should be quickly followed up by other forces for support.

Nagas and Driders can serve in the role of regular army ground forces - by putting sheer numbers on the battlefield, as well as adding their magic abilities to the fray.

Mermaid types can harass warships at sea.

Combined arms can also include devastating elemental support.

Also note that fairies in general make great infiltrators due to their ability to shrink down to three inches. Once having swarmed unnoticed into an enemy defense force, they can very suddenly grow to 100 feet and force the enemy to scatter, thus creating confusion, and most importantly, huge gaps in human/neko/elf formations - gaps that can then be exploited.



Human, Neko and Elf forces should at least factor these issues into their offensive and defensive strategies.