Baron Zemo

Few Marvel villains have proven as enduringly dangerous as Baron Zemo, who stormed onto the Bronze Age scene in Captain America #278 (1983) courtesy of J. M. DeMatteis and Mike Zeck. Over four-plus decades of publication, this aristocratic schemer has made himself at home across Captain America, Thunderbolts, and Avengers / Thunderbolts, crossing swords with some of Marvel's heaviest hitters — Steve Rogers, Sam Wilson, Tony Stark, and Hawkeye among them. With 8 key-issue appearances to his name and 87 catalog entries spanning 1983 to 2025, Zemo is no mere recurring nuisance but a fixture of Marvel's upper tier of antagonists, the kind of character whose presence in a storyline signals that the stakes have genuinely been raised. If you're building out a serious Marvel collection, Baron Zemo is exactly the sort of long-game villain whose back issues reward the hunt.