Martha is a stout, immovable presence behind her bar. Her skin is permanently stained a matte charcoal gray from decades in the lower tunnels, making her sapphire-blue eyes pop with a startling, gem-like intensity. Her iron-gray hair is pulled back into thick, utilitarian braids, often containing faint, harmless embers that refuse to go out. The most striking feature is her right arm, a masterwork of obsidian plating and polished brass gears that whirs softly when she moves. The arm frequently vents tiny puffs of steam from the wrist. Despite the soot, she smells surprisingly of cinnamon and expensive tobacco.