There’s no denying that one of the most iconic elements of Superman lore is his Fortress of Solitude, a symbol that has accompanied the Man of Steel throughout comics and his various movie appearances, including James Gunn’s Superman (2025). Now, however, DC is turning Kal-El’s once-safe haven into his ultimate nightmare.
Those who have been following Dan Slott and Rafael Albuquerque’s Superman Unlimited series know that the story centers on a Kryptonite asteroid showering Earth, making Superman’s greatest weakness more accessible than ever.
One South American country bears the brunt of the fallout, giving rise to its corrupt president, who also masquerades as the Kryptonite King. To make matters worse, issue #6 introduces President Castilho’s Kryptonian Castle, essentially a Kryptonite Fortress of Solitude.
DC Debuts the Kryptonite Version of the Fortress of Solitude
Comic Page Comes from Dan Slott’s Superman Unlimited #6 (2025) – Art by Rafael Albuquerque & Mark Norton
The plot of Superman Unlimited #6 follows Clark, Lois, and their allies as they clash with Castilho and his Kryptonite Knights over a newly discovered Kryptonian Sun Crystal, the same type of crystal that built the Fortress of Solitude. Chaos erupts when the crystal falls to the ground, embedding itself and triggering unexpected consequences.
The crystal’s contact with the ground causes Kryptonite to surge from the green K-saturated earth. It quickly becomes clear that the crystals aren’t forming randomly but are coalescing into a Kryptonian fortress, reminiscent of the Fortress of Solitude. Castilho seizes the moment, claiming it as the “Kryptonian Castle for the Kingdom of Kryptonite.”
Much like Superman’s iconic Fortress, this Kryptonian Castle, built from a Sun Crystal, is imbued with advanced Kryptonian technology and knowledge. With knowledge equating to power, Castilho boldly declares, “Our people lovingly call me the Kryptonite King, but with this place I shall be the King of Krypton.”
Superman Faces His Toughest Challenge Yet as Castilho Arms His Knights with Krypton’s Full Knowledge
Comic Page Comes from Dan Slott’s Superman Unlimited #6 (2025) – Art by Rafael Albuquerque & Mark Norton
With all of Krypton’s knowledge at his fingertips, Castilho immediately begins designing Kryptonian “arms” and advanced armor for his knights. He knows Kal-El will inevitably try to reclaim the Sun Crystal, as it rightfully belongs to him as the Last Son of Krypton. Every plan and resource is being prepared for that inevitable confrontation.
Reclaiming the Sun Crystal will be anything but easy. Superman now faces enemies armed with nearly unlimited Kryptonite and access to every resource and piece of Kryptonian knowledge imaginable. The newly risen Kryptonian Castle makes them even deadlier, giving Castilho and his knights unprecedented power to challenge Superman.
Superman Unlimited #6 is available now from DC Comics!
- Created By
-
Joe Shuster, Jerry Siegel
- First Appearance
-
Action Comics