Strontium-90

A mysterious figure who materialized in the early 1990s Marvel universe, Strontium-90 made their debut in Marvel Comics Presents #114, brought to life by the distinctive creative pairing of Ann Nocenti and Steve Lightle. That anthology series was a proving ground for edgier, more experimental corners of the Marvel cosmos, and Strontium-90 fits right into that Copper Age spirit of dark intrigue. With only a handful of catalog appearances, this is a rare, collectible presence — one who shares pages with heavy hitters like Ghost Rider and Logan — making those issues a fascinating find for fans who love digging into Marvel's more obscure, atmospheric corners.