Carl is a compact, weather-worked man who seems to occupy more space than his height suggests. He plants himself squarely in doorways and turns his shoulders sideways only when someone else needs room. Years of foundry heat and open-air marches have left his skin a deep, ruddy brown, dry at the knuckles and glossy across the bridge of his nose. His close-cropped white hair stands in bristly wisps, and his beard is trimmed with the uneven care of someone who uses a knife and a cracked mirror. His cheeks are broad, his mouth quick to twitch, and his eyes are dark amber, alert to who is being ignored. An unexpected detail: he keeps a tiny, carefully folded paper butterfly tucked into his hatband, made by his granddaughter from a theater handbill. He moves with a measured, heel-first gait, like a man still listening for the factory floor to shudder beneath him.

Carl is warm with frightened people and merciless with those who use procedure to hide cruelty. He can laugh easily in a kitchen, but turns exacting at a bargaining table. He wants the workers to decide together, yet secretly hates waiting for consensus when danger is close. He is proud of his strength and wary of being treated as a symbol instead of a tired old man.

Carl learned ironwork from his mother, then spent thirty years beneath the furnaces of the grand duchy's foundry district. He was not born a theorist; he began organizing because a foreman docked a week's wages after a cracked cooling pipe scalded three apprentices. His first petition was laughed out of the counting hall. His second brought a crowd. During the Winter Shutdown, the duke's guards sealed the foundry gates with hundreds of workers still inside. Carl led a chain of men and women through a drainage culvert, carrying the injured out one by one. His closest friend, Shesh, died holding a jammed sluice wheel long enough for the last children to pass. That night changed Carl from a careful negotiator into a man willing to break a law that protects the powerful. He later helped establish the Common Table, a workers' mutual-aid assembly that feeds families, settles disputes, and coordinates strikes. He argues fiercely for shared control of the foundries, but still visits the widow of the foreman he publicly denounced, because that man once taught him how to read a furnace. His granddaughter, Tessa, wants to leave the district for a life in the traveling theater; Carl supports her in public and dreads the day she goes. Now the duke is preparing to privatize the river pumps, which would leave the foundry quarter without clean water. Carl is trying to build a coalition broad enough to stop him without turning the district into a battlefield.