Warning: The following contains SPOILERS for the Superman and Lois season 3 premiere.The new Fortress of Solitude in Superman and Lois season 3 was revealed to have one particular upgrade that is more commonly associated with X-Men than the Superman Family. Superman has utilized a number of different remote Fortresses over the years, with most of them being located somewhere in the Arctic Circle. These Fortresses have likewise contained many exotic features, ranging from an alien zoo to an armory containing the many weapons Superman confiscated from his enemies over the years.
The new Fortress of Solitude first appeared in the closing scene of the Superman and Lois season 2 finale, after Clark Kent threw a crystal into the ocean to grow a new Fortress to replace the one destroyed by Tal-Rho. This Fortress, Clark had decided, would act as a second home and be accessible to everyone in the Kent Family, rather than just him and his super-powered son, Jordan. Despite that declaration, the first scenes showing off the new Fortress centered on father and son training and Clark revealing one of the new Fortress upgrades to Jordan. This upgrade, while uniquely Kryptonian, seems to be inspired by the X-Men comics.
