Manly Comics

Their star character

In the preface for the Flex Mentallo, Grant Morrison gave the history of the fictional publisher Manly Comics.
History
The company was founded by Ashley DuBois, the son of a wealthy landlord. The company produced comics based on Atlas, Hercules, Samson and Caligula. Ashley published the comics as an outlet for his homosexual desires (for example, a typical cover had Hercules whipping Atlas' butt with a flail). Much to his surprise, the comics were popular among soldiers and children, who missed the homo erotic subtext. Chuck Fiasco, an employee for Manly Comics, got the idea for Flex Mentallo from a neon sign he saw that said "Flex Mentallo". Flex Mentallo did decently after being introduced in Rasin' Men # 35. However, the introduction of his archenemy, Lars Lotus, led to "the Golden Age of Flex Mentallo". During World War II, Manly introduced patriotic characters such as Jap-Smasher, Yankee Poodle Andy and Lady Liberty. Towards the end of the war, Ashley thought the Axis power would win and published a comic where Jap-Smasher joined them. Naturally, they got lots of people angry. The company was forced to claim it was satire to avoid being accused on treason. During the 1950s, they introduced several non-superhero comics such as Web of Misery, Spurious Love Stories and Our Violent Fathers. A long lasting comic of that era was My Greenest Adventure, which had a gimmick where each story had something to do with the color of green. However in 1959, Flex Mentallo was reintroduced in My Greenest Adventure. This ushered the Silver Age of Comic Books. Wallace Sage became the writer of series. He introduced new villains (such as the TreeMen of Walzur, Mentallium Man, the Ism and revamped Lars Lotus) and wrote iconic stories such as "I, Lotus", where Lars falls in love with a woman only to be heart-broken when it turned out be Flex Mentallo turned into a woman via Mentallium. However, Flex's renaissance was ended with the story "Who Stole the President's Face?" (Flex Mentallo # 127), which was about JFK and was made right before the Kennedy Assassination. After introduced some sub-par characters, Wally Sage disappeared. Flex remained in comic book limbo until 1990. Grant Morrison reintroduced Flex Mentallo in his run of Doom Patrol for DC Comics. This led to Flex copycats such as Brute Brains the Psychic Weightlifter and Stress Psycho the Mindwrestler.
Reference
Flex Mentallo TPB