Black Fog is a supervillain appearing in Marvel Comics.
A serial killer haunting the streets of Hyderabad, India, the Black Fog was notorious and feared by the residents, though many had believed him to a myth. Eventually captured and imprisoned, his victims' families were allowed to visit him, with his jailers often looking the other way as they attacked him, leaving him scarred and limbless.
Sought out by Zero/One in her efforts to attack the Red Hulk, he was taken from his prison cell to her base on an abandoned Omnisapient Systems drilling rig where he was given cybernetic limbs to replace the ones he'd lost and physically rejuvenated to his prime.
Sent into battle Red Hulk in the Mojave Boneyard, Black Fog killed Red Hulk's LMD allies Gus and Chuck while engaging the Red Hulk, cutting him multiple times before Red Hulk was able to disable him. Beamed aboard a ship used by Zero/One, he was returned to the drilling rig where he was repaired in preparation for future use.
As Zero/One tracked Red Hulk to Manhattan, she deployed Black Fog to kill him following Red Hulk's defeat by Angrir. Seeking to protect his creation, M.O.D.O.K. Superior attacked Black Fog, briefly driving him off. When Skadi's Thule Society troops arrived, Black Fog attempted to attack the distracted MODOK Superior, but found himself incapacitated by Zero/One, who decided the best option would be for her forces (including Black Fog) and MODOK Superior's LMDs to team up against the Thule Society in an effort to save the future from what they deemed to be an inferior past.
Following Red Hulk to New Hampshire, Black Fog helped Hulk by attacking the intergalactic destroyer Omegex, an action sanctioned by Zero/One who found her need for vengeance to be an outdated emotion, left over from her time as a human.
When Red Hulk and ally Machine Man later tracked Zero/One to her floating base Ogygia, Black Fog was deployed to deal with them. During the battle, Machine Man was able to override Black Fog's control thanks to a device given to him by Zero/One's assistant Jacob Feinman. Finally free, he inflicted brief pain on Zero/One, allowing her to live as thanks for the enhancements and freedom she'd given him. Vowing to never be imprisoned again, Black Fog abandoned Zero/One to her enemies.
Black Fog was later believed active in Hyderabad, with multiple sightings of a strange fog being seen in locations where murder victims were later discovered.