The Benthians

The Benthians are one of the two sentient species indegenous to the deep oceans of the New Halifax colony. Benthians are small aquatic humanoids with squid-like faces. They share their home world with the Archipelians, shark-like humanoids living in the shallow waters surrounding New Halifax few islands. Both species evolved and reached sentience independently, their respective biotopes remote from each other. 

Although the Benthians look more like those guys, I
intend their narrative role to be closer to that of the
Mon Cal... Picture from Wookiepedia.

First contact between both species (beyond the odd Archipelians wrecks and bodies, crushed and deformed beyond recognition by high pressures, occasionally sinking to the bottom of New Halifax oceans and feeding Benthian mythology of surface demons) is a fairly recent event, rendered possible by technology (the Surface Race was a rivalry between the two main Benthian nations, locked in a decade long cold war, focused on attaining firsts in surface exploration, which were seen as necessary for national security and symbolic of ideological superiority).

Higher technology allowed the two Benthians dominant powers to establish colonies near the surface to facilitate access to its resources and their import to their metropoles. Exploitations of the Archipelians served as the excuse to a bitter series of conflicts known as the Haligonians Colonial War. Revolting Archipelians were rapidly joined by forces of other Benthians nations seizing a chance to end the two superpowers military and economical domination. Even whith those opportunity allies, the Archipelian technology remained little of a match for their enemies, and their allies industrial power base to small to make a difference.

The war would have been a short footnote in Haligonian history hadn't it be for contact with the alien Terrans. Those Oceanians and South-East Asians colonists quickly named their new home New Halifax (after the home town of the expedition leader's wife) and seeing an opportunity to break Benthian hegemony on the planet allied themselves with the Archipelians.

The war ended with the nominal defeat of the Benthians, forced to retreat in the depth of New Halifax oceans where their enemies can't operate efficiently and challenge them. With the Benthians out of the way, the Terrans quickly moved over to exploiting New Halifax resources, with little regard for their former allies claims.

When the Interstellar War reached New Halifax, the Archipelians quickly pledged loyalty to the Empire against the Terran Federation (and more than likely committing the very same mistake they did when allying with the Terrans). More surprisingly perhaps, the Benthians reluctantly cast their lot with the Terrans, perhaps fearing to find among the Empire multitude of alien citizens a species more suited to life in (and occupation of) their deep territories.

Infantry: 

I see the Benthians as a high technology force operating mostly outside of its native environement and thus relying relatively little on infantry, preferring to conduct operation through drones or from the safety of their vehicles. A small platoon (couple of squads and a HQ team, 20 something "men" in total) of 15mm.co.uk octopods will be plenty.

And perhaps a couple teams of those Seer Guards as elite/specialists... Pictures from 15mm.co.uk.

Vehicles: 

I wanted something original for them and ended up thinking about Spartan Games old range of Aquan Primes 1/10000 spaceships (I actually prefer the sleeker unadorned look of those ships to the more ornate newer one).

Benthians vehicles are in the first place bio-mechanical submarines able to use their powerful gravitic ballasts (gravitic projectors used to adjust buoyancy, trim...) to actually lift out of the water and operate above the surface or the ground. Designed for radical reduction of sonar reflection and flow noises, the surface of the vehicles also proved a challenge to detection by means of electromagnetic sensors, ensuring a fair level of stealthiness out of the water. Clusters of small sensors and blue-green laser domes provide advanced detection and offensive capabilities. Their system are powered by advanced fuel cells using hydrogen produced in the Benthians massive geothermal plants.

The smallest vehicle observed has been dubbed "Turret" by Terran forces and fills a niche somewhere in between a light tank and a fighter aircraft (while obviously retaining the option to submerge and operate as a small and swift attack submarine).

"Turret" light attack submarine. Picture from Spartan Games website.

The tip of the Benthian spear is the larger "Auger" (Terran reporting name, again), a main battle tank, attack aircraft and attack submarine all rolled into one sleek package.

"Auger" heavy attack submarine. Picture from manufacturer website.

Finally, because some operations just require the deployment of infantry, and to minimize the duration of any such deployment, the Benthians field the "Horseshoe" personnel carrier.

"Horseshoe" infantry carrier submarine. Picture from manufacturer website.

I still have to figure out how appropriate they are sizewise... I'm not overly concerned about the attack ones, they can be called "unmanned" (unsquidded?) drones, but the personnel carrier has at least to look like it can fit soldiers inside. Seeing the indicated length, the diminutive size of the Benthians, and unless the ship models are way to flat, that shouldn't be problem.

Painting scheme and markings: 

I actually love the paint scheme of the picture above. I'd maybe go slightly greyer and/or darker tone (more modern-submarinish but hopefully still maintaining that great organic feel) and have the laser domes blue-green instead of red (makes more sense for a weapon that has to work underwater). As for the marking, I'll either go with none at all (visual markings make little sense for mainly underwater operations, recognition is a purely acoustic affair for the Benthians) or a simple Terran Alliance roundel during the Interstellar War.

Terrain

I'll have to browse WW2 pacific galleries for more inspiration but I see a light blue pristine water covered table with clusters of low islands covered in alien jungles and ringed by sandy beaches.

I have a couple of bags of Critical Mass Games Alien Jungle Flora somewhere that look both alien and aquatic. They'll fit the theme perfectly. Perhaps with a bit of more conventional tropical vegetations imported by Terran colonists. 

Picture from manufacturer website.

I haven't any idea about what to do for Benthian structures yet: I'll just have them fight away from home until I find a suitable concept.

As for fauna, I might try to find a couple of second hand Games Workshop Tzeentch Screamers for a very nasty looking local critter, the Haligonian Horned Ray.

Picture from manufacturer website.