Ghosts have been an integral part of comics ever since the first appearance of a vigilante murderer named Casper the Ghost in the early 20’s. Due to a retcon and a more famous reboot brought on by the purchase of the title though, Casper is generally seen as a children’s character but stands as the launching point for ghosts in comics.
Many modern heroes follow in the path of Casper the Ghost such as The Deadmens, Jonah Hex, The Specter, and Susan Storm.
The Deadmens was started by Johannes Malkemus, a Russian immigrant who grew up on a dairy farm in South Carolina. Often beset with the vapors, Malkemus wrote and illustrated stories about the Boston Deadmens, a former circus trapeze artist who was killed for getting too close to the truth. With his ability to possess the living and the dead, he fought criminals and the power of the government as Malkemus was a heavily conservative person with little trust in the government. After 2 years of publishing the comic which was sold in a local gas station, Detective Comics purchased the character rights and reinvented the character as Boston Brand, the Deadman. Malkemus went on to drink the $100 he was paid for his character rights in one afternoon and died two days later of alcohol poisoning.
Jonah Hex was created originally as a ghost cowboy during World War 2 when a young man named Stan Ditko began drawing stories of a ghost cowboy who cared so much about justice that he could not allow himself to sleep. Ditko’s stories about Jonah Hex mostly focused on Hex floating through prison walls and punching out criminals who were trying to escape. When Ditko grew bored after 3 issues he packed the books away and left them at home where his parents sold them to Neal Adams who brought the character to the attention of DC offices and established Jonah Hex in All-Star Western.
The Specter is like Deadmans but with more blacksploitation. Literally reread the Deadmens article but with stock characters and you get the idea of the Spectre.
Susan Storm was sort of a ghost. What am I, wikipedia? I don’t know. Wikipedia stuff. Listen, if you don’t know who Susan Storm is, I can’t help you. Gosh.