Dekkun are large quadruped mammals who stand from six to quite impressive eight and a half feet tall at withers, and measure a bit over thrice that from snout to the tip of the tail, with the tail making up about a third of their full body-length. They appear agile despite their respectable size, with their bodies being elongated and, though powerfully built and muscled, remarkably flexible.
Their long tails are sleek, almost perpetually held high and horizontal to the ground, and shaped slightly like those of some lizards; their heads in return are very mildly reminiscent to those of horses' in shape, but with longer, mildly beak-tipped snouts and strong jaws filled with distinctively predatory teeth effortlessly capable of crushing bones. Where the ears would be positioned on a horse's head are actually two short, smooth, backwards-extending horns; their actual ears are mostly invisible against their maned necks. They also have small and almost unnervingly intelligent deep-set eyes.
Dekkuns' legs (and respectable shoulders and hips) structurally most closely resemble those of large cats. Instead of having paws, they however have long, thick fingers and toes covered in hard, resilient plating, and usually walk on the backs of their middle phalanxes - something which might on the first look leave the false impression of them being hoofed. This setting however also permits them to stretch their digits forward and use the length of those combined with the sharp, mildly curving claws they possess to climb impossibly steep cliffs and even trees, given that the latter are sturdy enough to support a dekkun's massive weight. Furthermore, their well-developed strong-clawed digits make very effective tools for tearing stuff (or beings) apart and digging, as well as give them some ability to hold things in hand, though the lack of proper opposable thumbs makes dekkuns' feet unsuitable for more complex tasks.
On rear feet, all five digits are used for walking, however on the front legs, only the three middle ones have the purpose. The outer digit of each of dekkuns' front legs has turned into a slightly curving, up to two feet long extendable blade, which is usually flipped back against the lower foreleg, and the inner one - the equivalent of thumb on human hand - has turned into a rigid downwards-curving spike hosting very strong, quickly paralyzing chemical.
Their bodies are covered in hard plate-like formations on the face and lower limbs, whereas on the rest of their bodies those formations become longer and start to overlap, with the back end of each 'plate' splitting into many softer and more flexible strands forming a quite functional fur-coat atop of the protective plating. On the neck, this topmost layer of fur becomes especially long and extensive, giving common dekkun almost lionlike manes. At the very tips of their tails, the plates often do not fully split into fur, but retain some of their rigidity.
Dekkuns' coloration varies greatly, with those found in areas of dense foliage being generally smaller and brighter-colored (patterns of green, dark red and dark blue) and those of plains being more massive and duller in color (patterns of dull yellow or light green, brown and blueish gray).