When Marvel introduced him in The Amazing Spider‑Man #129, he wasn’t a team‑player or a quip machine; he was a Marine with a mission, hired to kill Spider‑Man by the Jackal, and instantly unforgettable because of that stark white skull burning off his chest. Castle has become the medium’s definitive vigilante: a man with no powers who forces comics, film, television, games, and fandom to wrestle with the ethics of violence, the limits of justice, and the cost of never standin