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[b]Name:[/b] Nachthund
[b]Species:[/b] Canis noctis
[b]Rarity:[/b] No longer seen in the wild except on remote parts of Dust. However, common as [i]relatively[/i] domesticated animals on Ash and Isla Diablo especially.
[b]Behavior:[/b] Wary of strangers, will attack if provoked. Fanatically loyal to a human of its choosing and will fight to the death if need be.
[b]Location(s):[/b] Everywhere humans are.
[b]Key Points:[/b][list]
[*]Finally something that's relatively nice for a change.
[*]Rigid fur mats have over time essentially hardened into armored plates and will easily halt high velocity handgun cartridges and nearly any commonly found melee cutting weapon.
[*]Has no venom or anything of that nature, instead a highly septic bite that will rapidly cause extreme blood poisoning.
[*]Can see perfectly in near absolute darkness.
[*]Teeth and horns hard and strong enough to pulverize bone and penetrate mild steel plates.
[/list]
[b]Appearance:[/b] The Nachthund, despite a superficial similarity to the bloodhound, is anything but. Standing at the size of a large tiger, the Nachthund is genetically speaking still in the same family and genus as the bloodhound and old world dogs, its physiology has diverged dramatically. Originally a feral species, the Nachthund was somehow domesticated through means unknown and has now become a favored companion for adventurers needing a big friend, or simply people who want to be absolutely sure about their guard dog being an effective one. Covered in fur that has hardened and matted into what are basically overlapping armored plates, the Nachthund can in fact go toe to toe with some of Dust's and even Ash's nastier fauna. Also sporting large horns that curl under its jaw, the list of things that the Nachthund cannot disembowl or generally fuck up is a small one that includes monsters such as the A.D.T. Spider, or Armatapede. 

Also they're big enough to ride.

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[b]Name:[/b] Armatapede
[b]Species:[/b] Nobody's wants to get close enough to find out.
[b]Rarity:[/b] Uncommon, act as an apex land predator on the island of Ash and even on the southernmost end of Isla Diablo.
[b]Behavior:[/b] Highly aggressive apex predator.
[b]Location(s):[/b] Southernmost tip of Isla Diablo, Island of Ash.
[b]Key Points:[/b][list]
[*]Nope.
[*]Highly aggressive
[*]Well armored along entire body, resistant to handguns up to .44 Magnum
[*]Delivers a necrotoxic sting that, if it doesn't kill its victim simply from the wound itself, will result in agonizing death within hours without medical attention.
[*]180 degree vision
[*]No ability to hear, limited smell
[*]Can move rapidly in a straight line, slow to turn.
[/list]
[b]Appearance:[/b] The armatapede is one of Ash's most deadly land predators. Able to reach up to 20-25 meters in length and with scorpion like claws that can deliver a devastating cut or crush, or simply to hold prey still while it stings it. It has powerful jaws that are not unlike a pair of hydraulic shears, and a sting capable of easily piercing  centimeter thick plates of most common metals. The Armatapede is a burnt red coloration, with large black eyes. It is easily detected by sound if moving at top speed, the bug's legs and chitin clacking together create a harsh rattling sound that can be heard some distance off- even then, at that point it's often too late to run. 
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I had a few others in mind but they're a bit too 40k for the setting, I'll hold off on truly bad shit until later.