Charles Marlow
Marlow's name may be inspired by the Elizabethan playwright Christopher Marlowe. Conrad's father was a translator of William Shakespeare who doubtless would have known of Marlowe's work as well. Some intertextual interpretations of "Heart of Darkness" have suggested that Marlowe's "The Tragical History of Doctor Faustus" may have influenced Conrad. Charles Marlow describes a character as a "papier-mache Mephistopheles", a reference to the Faust legend. Marlow's and Kurtz's journey up the Congo River in "Heart of Darkness" also has similarities to another work by Marlowe, "Dido, Queen of Carthage", in which Aeneas is stranded on the shore of Libya and meets the African queen Dido.
Jack of Hearts
Jack of Hearts, real name Jack Hart, is the son of scientist Philip Hart who created "Zero Fluid" and an alien woman from the Contraxian race. As a young man Jack was doused in Zero Fluid and gained super powers but was not in total control of his powers. In an attempt to control his powers Jack of Hearts built a containment suit that resembled The Jack of Hearts playing card. The lack of control became a recurring theme with Jack of Hearts, including his stint in the Avengers where he had to spend 14 hours a day in a containment room to prevent self-destruction. When his powers became uncontrollable he chose to leave earth, exploding in space without harming any innocent bystanders.