The hardest part of fighting Superman is how his weaknesses are traditionally limited to red sunlight, Kryptonite, or magic, but it turns out that the Man of Steel has been hiding a fourth option all along, one that's far more effective.
Everyone knows Kryptonite is the best way to take down the Man of Steel. If someone gets their hands on that radioactive green rock, it's a pretty good way to damage Superman even through his invulnerability. The problem is that getting the rock is absurdly difficult. Not only is the mineral naturally rare to come across, but considering it's the remains of an exploded planet, Superman and the Justice League have been doing their best to collect any stray Kryptonite to keep it out of the hands of villains. And while red sunlight and magic can also damage Superman, they're not easy to come across either. Red sunlight lamps can be easily destroyed and finding an evil magic isn't a simple feat. But it turns out Superman has a worse weakness than Kryptonite, one that is much easier to come across, comparatively.
Superman Loses His Powers Due To Sunstone
This hidden weakness is revealed in 2010's Superman: World Of New Krypton #12 by Greg Rucka, James Robinson, Pete Woods, and Ron Randall. This issue involves the long-awaited conclusion to a conspiracy that seems to be tearing New Krypton's society apart. Key of the government are being assassinated and the labor guild, New Krypton's primary workforce, is being framed for it. It turns out that the perpetrator is a high member of the government, who decided to betray New Krypton for a position of power on Earth. When Superman finds this out, he goes to confront the perpetrator. Superman is then surprised by a secret weakness that even he doesn't seem to know about. It turns out that sunstone, the material most Kryptonian architecture is based on, can be synthesized to have a similar effect to gold Kryptonite, which removes a Kryptonian's powers for a set amount of time. This leaves the Kryptonian completely vulnerable and powerless, and the worst part is sunstone is much easier to get than Kryptonite.
Sunstone is what the majority of Kryptonian architecture and ships are based on, which includes the Fortress of Solitude. Not only this, but Lex Luthor himself once gained an entire battleship made of the substance. Given how crafty Lex is, it's unlikely he didn't take some to keep for himself. Green Kryptonite is undeniably dangerous, as it makes Superman physically ill and slowly saps him of his strength. However, Superman is still very durable, even under the effects of green Kryptonite. On the other hand, the effects of gold Kryptonite remove one's powers entirely. This includes the invulnerability that Kryptonians have, meaning that Lex could just hit Superman with sunstone and then kill him with a regular gun or knife. This is significantly more threatening than green Kryptonite. When Superman is hit with the synthesized sunstone, he really has no response to it. He is entirely helpless, and the only reason he isn't killed is that he expected something like this to happen and has called in backup, which just proves how powerless he is against it by himself.
Superman Has Back Up To Save Him
While most people think Kryptonite is the best way to kill the Man of Steel, it turns out that Superman has been hiding a far worse weakness in the DC Universe for a long time.
