Alexander Luthor Sr.

Few characters carry as much weight in DC's cosmic mythology as Alexander Luthor Sr., who stepped onto the page in 1986's The Official Crisis on Infinite Earths Index — a Copper Age debut that places him squarely within one of comics' most ambitious universe-reshaping events. With only a handful of catalogued appearances spread across nearly three decades, he's a rare, select presence, surfacing in landmark reference works like Who's Who: The Definitive Directory of the DC Universe and the villainous ensemble of Forever Evil, sharing pages with titans like Clark Kent, Wonder Woman, and The Flash. His scarcity makes every appearance count, and for collectors and continuity devotees alike, he represents exactly the kind of deep-cut DC figure whose significance far outstrips his page count.