Despite evidence to the contrary. A giant squid made a selfie, or a picture of his/her mate or mum or a campaign poster from carefully arranged shark vertibrae on a shallow sea bed millenia ago. Presuming intelligence to be new, unique or land based is arrogance. Did they go extinct? Deeper? Or migrated to the vast deeps of the solar system. If we catch up to them in Europa lets hope they are friendly and not want their real estate back.
Back when life evolved around the vents. What intelligence's, what civilisations arose? We know species are found in common. Could they have sent out generation ships into their dark void in search of new worlds?
Nemo's crew need a source of aquafiddlyum. Here is a rock with a pure vein of it. But the locals consider it sacred and prepare to defend it.
Nemo's troops are the usual Q4 C2, guns Medium +2. Not move & shoot but no reload. I toyed with making them mooks, one hit wonders to account for the effects of environment.
Fishmen guns Short +3 single shot. Cannon +6 first target, +5second, etc. 6 reload 3 crew. Crabs & lobsters +4. Flying squad halberdiers +3. All other weapons presumed to require bracing so sea floor only.
In comes blue squad, to be attacked by the crabs. One gets short and the rest come on, getting the better of Nemo's troops. With a mighty whoosh the flying (well swimming if you want to be pedantic) swoops on the greens, scattering them. Four go down and 2, the officer & a crewman, start a running battle until the crewman is killed and the officer surrounded and captured to face a gristly fate on the altar of some dark, deep deity.
One green survivor has a ding-dong running battle with a net-armed scout a crab and its handler, finally gets away!
And the time the predators are circling. Do you like these? From GZG, a fleet based on the original drawings in Full Thrust, but never released other than a special at a Salute, many moons ago. I think my bamboo & rest make ideal sea plants. I'd been intending to make stage trees with the big green pompoms-.
The red squad move up but the hidden cannon goes boom (split water-recombine, enough chemicals react violently with water, glass vial-smash-boom.) sending half of them to hell. The rest are faced with the armoured crab men. Grey squad, alerted to its presence, takes out the cannon and moves on to decimate another unit.
Alas, Nemo's forces are now too weak and scattered to achieve their goal and must retire.
Real fun. Quick, easy game.