I'll save RTVoril the trouble and say right now: tl;dr. We'll see you next week, for anyone else with time on their hands though, read on.
Some ways back, I tried to shoehorn my beloved Grymn minis into 40k in the form of an allied race to the Tau (with fluff to justify it here). Well....that didn't work too well. Of course, any infantry (w/o anti-tank weaponry on hand) that has a Furioso drop pod into pointblank range and attack them, isn't going to fare too well either. I dunno, it just felt kinda forced, especially as I was fielding them as Tau with different weapons.
As such, they've spent their lives since on the shelf looking cool but...not much else (I still need to finish my Grymn Mawe Walker as well). Then, GW released the Inquisition codex, and once again I can field virtually anything in the form of one of my Inquisitorial Circus Side Shows (who are invariably allied to my GF's Tau).
Not wanting to just toss the old fluff and say 'they're inquisitors now' I instead opted to update my Grymn fluff to represent their change in wargear, stats, etc. Not to mention my new Grymn that I'll be using as my 'Prospector-General' (Counts-as-an-Inquisitor) which you can see here:
|As much as I liked the Power Armored Grymn, the models just didn't look complete till they added the backpack bit. Speaking of, the 'railgun' (hell rifle) is perfect for my fluff!|
So here is the Grymn's story, picking up right after the fluff linked above left off...
Recent sightings of the Grymn however have found them to often be at odds with their Tau allies. Indeed, they now only fight along side one another only in the most dire of circumstances. Even then both factions will keep their distance from one another whilst keeping a wary eye for treachery. It is unknown as to whether or not the Grymn are still considered a part of the Tau Empire or not. In an all out war, the Grymn would stand little chance against the Tau's numerical and technological superiority. However it is believed by some members of the Ordo Xenos that the Grymn may be trying to secede from the Empire.
As a result, notable changes to the Grymn's combat doctrines have been observed in recent years. In addition to keeping their distance from the Tau in general (as opposed to relying on the Tau for protection), the Grymn's weaponry has undergone a myriad of changes. The Grymn's carbine weaponry for example, no longer functions as little more than a pistol (by human standards). Now thru the use of improved ammunition technologies, their carbines are of comparable potency and function to an Imperial Guard issue hot-shot lasgun.
Curiously, and quite at odds with the improvement of the individual Prospector's personal fire power, the Grymn' Prospector's body armor seems to be bereft of their trademark Iridium alloy. Instead it is built rom a composite weave of plastics and ceramics, to form a hard yet light weight shell. Whilst visually the same as their iridium armor of old, the newer materials have an overall reduced quality in terms of ballistic and impact protection. The Ordo Xenos has theorized that the Grymn's reserves of iridium alloys have either been depleted or else lost to Tau control (quite possibly causing the schism amongst the two races).
Despite this lack of personal protection, the Grymn have recently become a bit more aggressive in their willingness to engage in hand-to-hand combat. Whilst still not a particular threat in that method of warfare due to their small statures, they do fair better than the average Tau Fire Warrior (not that that's saying much). As such, another notable change in the Grymn's arsenal is the inclusion of power weaponry. Whether these weapons were reverse engineered from captured specimens, or wholly indigenous designs is unknown. Regardless, the Grymn no longer have any moral issues with engaging in close combat, unlike their former allies.
Another significant change is the Grymn commander's (who have been retitled as: 'Prospector-Generals') preference in battlefield equipment. Power armor, rather than the heavier Mawe walkers of old are apparently now standard issue equipment. Instead of the bulky, and exceptionally heavy armor plating, as well as the short ranged barrage of vulcan cannons on the Mawe, Grymn power armor (the design of which this galaxy has never before witnessed) offers commanders improved mobility and versatility (at the expense of brute force). Lacking the black carapace of the Space Marines, Grymn power armor appears to be instead comparable to that of the Adeptus Sororitas.
Whilst the weapons load of power armored Prospector Generals varies according to personal tastes and/or mission requirements, usually it comprises of a power weapon, grenades of various types, and a new light railgun of apparent Grymn design. The railgun was no doubt created in emulation of their former Tau allies. When firing the railgun, the commander must remain still in order to maintain accuracy. This can temporarily limit the his/her mobility. It is capable of penetrating lightly armored vehicles, and Space marine power armor. Despite its mobility issues and low rate of fire, this is a potent weapon that should not be underestimated.
Another sign that all is not well within the Tau Empire, is the apparent alliance among the Grymn and the previously rumored Xenos species called the Nicassar. There have been rare reports of Nicassar vessels working in conjunction with the Tau made by Rogue Traders, and even more rarely the Imperial Navy in the years following the Imperium's first encounter with the Tau Empire. It seems the Tau has gone to great lengths to hide this psychic species from the Imperium. Not so the Grymn. Via battlefield pict captures, there has been evidence of Grymn commanders conferring with small numbers of an unusual, semi-levitating, tentacled species. Whilst often armed with a small pistol or the like, these weapons are believed to be only for personal defense, if they're even used at all. Instead, this new form of vile Xenos appears to be highly evolved psychicly, and can wield potent magics against hostile forces. Consorting with such a dangerous species is more than enough to warrant the Grymn's (and the aforementioned Tau) need for extermination!