Warning: contains spoilers for Action Comics #1030!

Superman's biggest secret can't be exposed, otherwise, the entire DC Universe could come under peril. The Man of Steel is trusting Batman and the Atom with the shocking news he's getting weaker and dying after being poisoned in his latest fight. If the information regarding his health falls into the wrong hands, villains like Darkseid could attack Earth while its greatest defender is weakened.

Superman was injured in Action Comics #1029, while protecting a S.T.A.R. Labs research satellite which inadvertently opened a breach, allowing aliens to seep through and attack. The breach was dangerous to Superman, as it made him vulnerable to attacks. Meanwhile, Superboy has the knowledge from his time in the far future with the Legion of Super-Heroes that his father will die, as history books suggest he was set to die on the same day. After the breach is sealed, Superman tells him maybe Superboy's presence is what changed his future fate. However, the series' next issue shows Kal-El isn't in the clear.

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In Action Comics #1030 by Phillip Kennedy Johnson, Daniel Sampere, Jordie Bellaire, and Dave Sharpe, Superman tests his strength as Atom and Batman watch, but doesn't get the news he's hoping for. Batman reveals his speed and levels of force have dropped while noticing a small cellular decay in Superman. Atom tries to soften the news by telling him it could be the normal fluctuation in his solar cycles, but Batman disagrees. He says the cellular radiation is "consistent with radiation poisoning," with the fight in the breach likely causing the situation. Superman asks Batman to keep the news between them, as if a villain finds out, they'll attack earth knowing he's weakened.

Batman Atom Superman

Superman knows if the secret gets out that he's dying, then it could be open season for DC's biggest villains. The conversation specifically mentions Lex Luthor and Darkseid as those who would take advantage of the knowledge. But readers learned in the last issue Superman is being closely monitored by another villain, Mongul, and now know he's working with a mysterious deadly villain.

With the news Superman's cells are getting weaker, it seems like it's just a matter of time before his predicted death is about to occur. Until it does, or the rest of the Justice League, Superboy, or someone else finds a solution, the biggest secret in the DC Universe will have to be kept - otherwise, an attack seems imminent. Without Superman at full strength, Earth loses its greatest defender. Thankfully, Batman is an expert at keeping secrets, so don't expect him to suddenly accidentally blurt out the news.

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