Vault

Dark fantasy 3D concept of a Soul Vault in a necromancer fortress. A low, heavy stone structure with a reinforced front door made of iron and bone. Above the door floats a small inert soul crystal held by chained runic clamps. Walls are thick, cracked, with engraved containment runes glowing faint blue. Two squat warding obelisks flank the entrance, unlit and dormant. Ground around the vault is scarred with circular sigils marking safe-storage zones. Stylized semi-realistic, oppressive, isometric or top-down, high detail, no characters.