Doctor Yen

A Silver Age creation born from the legendary partnership of Stan Lee and Don Heck, Doctor Yen made their Marvel debut in The Avengers #29 back in 1966 — stepping onto the page alongside some of the most iconic names the House of Ideas had to offer, including Goliath, the Scarlet Witch, and Janet Van Dyne. Though appearances in the catalog are rare, this character has surfaced across an impressive span of Marvel history stretching all the way to 2019, turning up in collections that celebrate the art of John Buscema and the sweep of the Black Widow's adventures. For the dedicated Marvel completist, Doctor Yen is exactly the kind of deep-cut Silver Age figure that makes hunting through back issues so rewarding — a genuine piece of the era when Lee and Heck were building the Avengers' world brick by brick.