(Jungle Comics 007, 1940)
Camilla, Queen of the Lost Empire, having made the transition from capricious villain to noble hero and staved off a couple of attempts on her throne and her life, is getting ambitious. She is determined to descend into the Cave of Sighs, a local portal to Hell, and banish the Devil from her lands.
Together with the reformed assassin Caredodo, Camilla passes the Copper Gates of Hell after a brief encounter with one of my favourite things: an anthropomorphic personification! Specifically, they encounter Temptation, who almost ensnares poor Caredodo with her wiles and mug of delicious-looking potion before Camilla sends her packing.
Also there to greet them is Mephistopheles of Faust fame in a much more charming turn than comic book demons usually get to be, probably as a deliberate contrast to the main attraction, the Devil himself, in a wildly more grotesque form than one usually sees in comics before the late Sixties. Ordinarily, your Devils and Satans are a lot closer to Mephistopheles there than this soggy lump of flesh and even the more monstrous of the bunch are still red humanoids along the lines of MLJ's Devil.
The Devil wants Camilla's help to escape into the world of man and take over the place. Ambitious, sure, but a bit pedestrian for Satan himself. What use is temporal power to the Lord of Hell?
In a slightly odd turn of events, Camilla defeats the Devil by hewing a cross out of stone and holding him at bay with it. Since Camilla originally worshipped Thor and the other Norse gods and later restored her empire with the aid of the pantheon-unspecified god Bal, I had assumed that the Lost Empire was established some time before the conversion of the Norse to Christianity. I'd be tempted to blame that pill Jon Dale for converting her but she has engaged in some paganism since his departure from the strip, so I am forced to conclude that Camila subscribes to some sort of syncretic faith that incorporates elements of many religions. Fun!
(This is also the mission that ends with the Angel of Faith rewarding Camilla by transforming Caredodo from a Nottie to the Hottie Sir Champion, in case you were curious about when that happened)