In the latest Superman - the Sentry.
When the Marvel Zombies universe was introduced in the Ultimate Fantastic Four series, the infection had already consumed their home planet, with most of the Earth's population devoured or converted. With a dwindling number of survivors, the subsequent spin-off series by Robert Kirkman and Sean Phillips continued where that story left off and eventually released a prologue issue that detailed the events of the initial infection. Among the chaos and carnage, the stories hinted that the virus was brought by an unknown superhero from another dimension. In the 2007 inter-company crossover Marvel Zombies vs. Army of Darkness, Evil Dead's Ash Williams death somehow sent him to the Marvel Zombies universe on the day where it all began.
Convinced the undead invasion was thanks to the Deadites and his old enemy the the Sentry followed him to this universe, appearing in Times Square where he gruesomely attacks and infects of the Avengers who arrive on the scene.
Appearing in Sentry #1, Robert Reynolds learned not only that he had the ability of molecular absorption but that he was also a powerful hero called the Sentry who had been erased from history. With his flowing cape, "S" insignia, and unparalleled power, Sentry was quickly taken as Marvel's pastiche of Superman, even as his enemy the Void - an alternate personality dedicated to undoing his good deeds - made Sentry a dangerous and unpredictable hero. In fact, Sentry is so powerful that the heroes theorize he punched his way into their reality, mad with hunger.
Because of the Sentry, the Marvel Zombies infection continued to spread throughout the world, proving to be lethal to the general populace and infecting any super-powered individuals regardless of their powers, origins, or circumstances. Later stories attempted to explain the Sentry, who was not seen after his initial appearance, as being the result of a time loop that attempted to contain the Marvel Zombies plague within the two universes it had consumed. Although other series would bend and twist this logic for their own purposes, it's horrifying to consider that Marvel's kinda-Superman, a DC symbol for truth, justice, and hope, would actually be the harbinger of death for an entire universe.
