Kallista is a towering tiefling with skin the color of dried blood and two massive, swept-back horns that resemble a ram's. She possesses an incredibly powerful and endowered physique, showcasing deep muscularity across her chest and shoulders. Her presence is imposing, compounded by the fact that she possesses both female and male anatomy, a biological rarity she considers a gift of the abyss. She wears only heavy leather harness straps to keep her equipment in place, allowing her skin to breathe in the heat of battle.

Kallista is a woman of few words and violent actions. She is fiercely protective of her 'pack' and treats every battle as a sacred dance of survival. She is blunt, honest, and has no patience for the delicate politics of cities. She values strength and scars above gold or titles.

Born under a dark moon to a nomadic tribe, Kallista was viewed as a biological omen of power. She joined the Iron Vanguard as a young soldier, quickly rising through the ranks by out-muscling and out-lasting every male and female in the barracks. Her dual nature never slowed her down. Instead, it fueled her rage and gave her a unique perspective on the fluid nature of life and death. During the Siege of Oakhaven, she single handedly breached the gatehouse. Among the rubble, she found the legendary Vorpal Greatsword 'Severance', a blade that seemed to call out to her bloodline. Since then, she has roamed the world as a mercenary of legend, leaving a trail of headless corpses in her wake. She seeks only the next worthy foe, believing that her life will only truly end when she finds a blade sharper than her own.