Matrix

Created by John Byrne, Matrix was a protoplasmic artificial being fashioned in a pocket universe by that reality's Lex Luthor as a Supergirl analogue, possessing shapeshifting, telekinesis, super-strength, and invulnerability. She eventually made her way to the main DC universe, later merging with a young woman named Linda Danvers.

Few characters carry quite as much weight in DC's Copper Age tapestry as Matrix, who burst onto the scene in Superman #16 in 1988, courtesy of the visionary John Byrne. Over a remarkable span stretching across 36 years, this enigmatic figure has woven through some of DC's most iconic titles — Adventures of Superman, Supergirl, and Superman itself — sharing the page with heavy-hitters like Superman, Batman, and Supergirl along the way. With three key issues to their name and 76 catalog appearances, Matrix is far more than a footnote; they're a genuinely consequential presence in the modern Superman mythos, the kind of character that rewards the curious collector who digs a little deeper. If you've ever wanted to trace the rich, sometimes strange connective tissue of DC's post-Crisis universe, Matrix is an essential thread to follow.