Rex

Few debuts carry the weight of sharing a first chapter with Hellboy himself, but Rex — born in the pages of The Dark Horse Book of Hauntings in 2003 — entered the Modern Age of comics with exactly that kind of distinguished company. A Dark Horse original brought to life by Mike Richardson and P. Craig Russell, Rex has kept remarkable companions over the years, rubbing shoulders with the likes of Orphan, Jack, Whitey, and Ace across stories collected in the beloved Beasts of Burden omnibus. It's a small but choice catalogue of appearances, and the crossover with Hellboy signals just how seriously Dark Horse took this corner of their universe from the very start — over two decades later, Rex remains a quietly enduring figure worth seeking out.