This isn't a story about Superman's "Fortress Of Solitude"*. "Fort Superman" is like another version of Fort Knox. This story contains a number of super-menaces that Superman was supposed to have encountered before, but I'm not sure if they all were actually in previous comics. Dragons were a recurring thing, but it wasn't always the same dragon.
Again Superman says he has to teach Lois Lane a lesson, and Jimmy Olsen as well. It's actually kind of odd that they put so much emphasis on that business when Superman really should be more focused on reforming the bad guys rather than trying to transform the people that are already supposed to be on the side of right. Of course Superman would also like to reform Luthor, but then, if that happened they wouldn't be able to have him being a bad guy in the stories.
Art by Wayne Boring.
*Doc Savage had it first, in the pulp magazines. Superman borrowed a number of elements from Doc Savage, including having a girl cousin who helped out in some of his adventures.
A