The X-Man Kurt Wagner known as Nightcrawler, grew up in a circus. Kurt’s adoptive mother Margali Szardos, was a Romani sorceress that worked as a fortuneteller in the Herr Getmann’s Traveling Menagerie. She raised the baby Kurt with her two biological children, Stephan and Jimaine. Kurt loved growing up among the circus folk, who accepted his looks. His agility and flexibility grew and he became a talented trapeze artist. The crowd assumed he was wearing a costume.
Johnny Blaze was originally a stunt motorcyclist at the Quentin Carnival, later coming to own it. The Quentin Carnival was one of America's more popular traveling festivals, having toured the country for more than twenty years. Although the carnival enjoyed great fame, it was also the target of great discord. On more than one occasion, the carnival became the backdrop of great battles between the mysterious Ghost Rider and various nefarious beings.
Circus trapeze artist Boston Brand performed under the name Deadman, a stage persona that includes a red costume and white corpse makeup. When Brand is murdered during a trapeze performance by a mysterious assailant known only as the Hook, his spirit is given the power to possess any living being by the Hindu god "Rama Kushna" to search for his murderer and obtain justice.
Clint Barton ran away to join the Carson Carnival of Traveling Wonders. Clint soon caught the eye of the Swordsman, who took the young boy on as his assistant. Along with the help of Trick Shot, the Swordsman trained Clint to become a master archer. Clint adapted his archery skills to become a star carnival attraction, a master archer called "Hawkeye", otherwise known as "The World's Greatest Marksman". He witnessed Iron Man in action and was inspired to become a costumed hero.
Richard "Dick" Grayson, the original Robin. He still returns to the circus whenever they pass by Gotham and Bludhaven. He even ended up using his sizable trust fund to buy them out to save them from financial ruin. He's generally regarded as the world’s greatest acrobat, and having the best butt in comics.