Kostchtchie destroying trespassers in the Iron Wastes. He had decreed that frost giant females of tribes under his control were to be fed to his warriors when they become too old to bear children. He was known to be extremely misogynistic. For example, despite knowing that his realm, the Iron Wastes, was an infinite plane, he was still obsessed with trying to conquer all of it. Kostchtchie was ambitious, but prone to idiotic fixations which distracted him from his larger goals. Kostchtchie was particularly attached to his massive enchanted warhammer, known as Matalotok. He was known to be easily amused, and would sometimes even spare lesser beings if he found them humorous. However, he was petulant and childlike in many respects, and these rages often resembled demonic tantrums. Befitting his title as the "Prince of Wrath," Kostchtchie was renowned for his rages. He was desperate for power and validation, but fearful in the face of powers greater than him. Kostchtchie was a hateful, imperious, and violent dullard who reveled in the frenzy of combat.
He always carried with him a massive hammer. His head was malformed and his face was flat, ugly, and hairless except for his eyebrows. Kostchtchie was a 24‑foot (7.3‑meter) tall muscular brute with hunched shoulders and stubby, bowed legs.