"Doctor Strange & Doctor Doom: Triumph and Torment" was a Marvel Graphic Novel, published in 1989, starring Doctor Strange, earth's sorcerer supreme, and Doctor Doom, frequent Marvel Universe villain. In this case, however, Doctor Doom is a co-protagonist and heroic figure in the story.
The graphic novel format allows a more meandering format, and this tale has a framing story where The Aged Genghis, an old sorcerer, recounts his first meetings with Doctor Doom and Doctor Strange. He then disappears, flying away, while magicians of different stripes around the world here a psychic call. Over the course of several days, they all converge on a jungle temple in Southeast Asia, where they are pitted together in a magical tournament. These include Doctor Doom, who, along with his scientific knowledge, is a magician. As a side-effect to his participating in the tournament, Doctor Doom receives a favor from Doctor Strange, which he uses to ask Doctor Strange's help in freeing his mother, who is imprisoned by the demon Mephisto.
After having established this, the main story is Doctor Strange and Doctor Doom going to hell, where they fight Mephisto in an attempt to save the soul of Doom's mother. This is a battle that involves both physical action against swarms of demons, as well as wrestling with moral quandaries and the nature of the soul. The ending of their struggle is a somewhat mixed success.
Since this is October, I think it is fair to analyze this story as a horror story. This involves, after all, a trip to hell and a struggle with a demon. The extended storytelling and closer attention to art allow more atmosphere than would be possible in a monthly title. But the problem in turning this super-hero story into a horror story. The reader might at times wonder: how is Doctor Strange firing mystic bolts of force at Mephisto different than Iron Man shooting repulsor beams at an alien invader? How is Doctor Doom's bombastic speeches declaring his power different when leveled against the devil different from his fisticuffs with The Thing? Although the story stands well on its own, part of the problem here is that the wide-spanning nature of the Marvel Universe takes away from the piquancy of the story of Doom's love for his mother. How seriously can we take this story when the next month we might see Doom get a face full of webbing from a wise-cracking Spider-Man.
However, as I recently mentioned, this is the perspective of me as an adult. When I was reading comic books when I was eight or nine, anything beyond the usual spandex-clad punching matches of the usual, $1.00 issues of my favorite heroes was slightly mysterious. The graphic novels were up on the walls at comic book shops, outside of my financial and literal reach. For the intended audience at the time, this story would have probably been mysterious, even menacing, in its psychological aspects and depictions of hell.