The Istania are a race easily set apart by their crystalline features and elemental affinities. While their proportions mirror those of humans, their forms are more striking and varied. They typically stand between 157cm and 182cm, though interbreeding has created a wide range, with extremes spanning from 135 cm to 205 cm. Their weight is proportional to their height, often leaning toward muscular builds due to bones subtly altered by crystallization. Tieflings mature at about 21 years of age and, though only slightly longer-lived than humans, may reach up to 110 years.

Their most distinctive traits are their crystalline “pontil marks,” or more commonly referred to as Echo marks, which are formations that manifest along the head and lower back, extending into a tail. These structures are remnants of the primal arcane surge that birthed their kind, channeling energy through the body in intricate patterns across the face, neck, and spine. Echo marks most often resemble precious or semi-precious gemstones, spiking outward in varied shapes. While prominent at the horns and tail, smaller growths may also appear at the shoulders, elbows, knees, hips, hands, and feet. Sometimes even forming geode-like cavities in the ribcage. . .

"Echo marks, faded though not forgotten, each Therianid and Istania have these on their napes and cheeks... Some believe they're kissmarks left by the Flux Incarnate upon these souls as a sign of their undying love... Even though they've long since vanished since the First Shattering..."

Horns themselves are always present, rooted in keratin near the skull and fracturing into crystalline tips of unpredictable form. Tails vary just as widely, their tips ending in; spikes, spades, tufts of hair, or sharp crystalline shards. Their leathery surfaces typically match the Istania's skin palette.

Skin tones are extraordinarily diverse, ranging from human-like hues to vivid colors across the spectrum, sometimes streaked with unique markings akin to their alchemical sigils. Their eyes are glass-like and prismatic, refracting light as if cut from crystal. Some display multiple fractal irises within a single sclera, which is most often black or white. Ears may appear pointed from crystalline clusters at their tips, though some Istania bear rounded ears instead. Subtler traits such as sharpened canines, faint patterns along the skin, or uncommon scleral colors, further distinguish them.

Every Istania is born with an affinity to a specific crystal or gemstone, which shapes not only their horns but also their elemental inclinations. A citrine or ruby-marked Istania may show a talent for fire, while those bound to opal or aquamarine lean toward water. Amethyst and lapis lazuli are tied to air, while agate and malachite resonate with earth. These affinities ripple through their bodies, often influencing physical traits: fire-aligned Istania may carry flickers of ember in their hair, while water-aligned individuals might have horns that shimmer with condensation or even drip with seawater. In rarer cases, some Istania embody moonlight or shadow, their forms exuding an otherworldly beauty.

Though each is unique, the Istania are unmistakable. Horns of stone and crystal, refractive eyes, striking skin tones, and the glittering pontil marks of their genesis ensure they stand out in any crowd as living embodiments of magic crystallized into flesh.