Real Name: Brigid O'Rielly
Occupation: Former police detective, now vigilante
Identity: The public is unaware of O'Rielly's existence as Mayhem.
Legal Status: Citizen of the United States with no criminal record, believed dead
Other Aliases: None
Place of Birth: Unrevealed
Marital Status: Single
Known Relatives: None
Group Affiliation: Ally of Cloak and Dagger
Base of Operations: New York City
First Appearance: (as O'Rielly) CLOAK AND DAGGER Vol. 1 # 1, (as Mayhem) CLOAK AND DAGGER Vol. 2 #5

History: Brigid O'Rielly was a police detective in Manhattan's 21st Precinct. She learned that two strange vigilantes were attacking pimps, pornographers, and drug pushers in her precinct. Finally, she saw the two vigilantes, Cloak and Dagger, fighting "chickenhawks" who had gathered together a number of runaway children they intended to exploit. In the course of the battle, one of the children was killed by a stray bullet. Although neither Cloak nor Dagger had fired the shot, O'Rielly blamed them for the boy's death, claiming she could have saved him if not for their interference. She was now determined to capture Cloak and Dagger, but they teleported away.

Later, Cloak and Dagger came to O'Rielly to seek her help in tracking down Duane Hellman, who was poisoning aspirin used by children. O'Rielly cooperated, but was appalled when Cloak swallowed Hellman up in the darkness within his cape, sending him into another dimension. O'Rielly decided to bring Cloak and Dagger to justice, but later decided against arresting them when Cloak gave up Hellman to her. After Cloak and Dagger told her their origins, she resolved to trouble them no longer.

Later, O'Rielly and other police officers investigated a warehouse allegedly containing millions of dollars of illegal drugs. The warehouse belonged to Marshall Pharmaceuticals, formerly owned by Simon Marshall, whose experimental drug had given Cloak and Dagger their powers. In the warehouse O'Rielly and the others were entrapped by corrupt policemen including Roger Falcone, who were in league with the Maggia family smuggling the drugs. The four captives were exposed to a gas created by Marshall in order to asphyxiate them. Furious at Falcone, O'Rielly said if she could escape, she would not wait for a judge and jury but punish him herself. She said, "The mayhem I'd cause would purify the whole department of your kind." Her three fellow captives died due to the gas.

Cloak and Dagger found O'Rielly near death. To protect O'Rielly, Cloak surrounded her and Dagger with his darkness, and Dagger tried to revive her with her "living light." But O'Rielly died, only to rise alive but transformed into the being calling herself Mayhem. Mayhem aided Cloak and Dagger in fighting Falcone and his two accomplices, and Mayhem killed Falcone.

Mayhem has allied herself with Cloak and Dagger in hunting down dealers in illegal drugs. Mayhem is herself now a vigilante, showing no mercy to the criminals she pursues.

Height: 5 ft. 4 in.
Weight: 120 lbs.
Eyes: (as O'Rielly) Green irises, (as Mayhem) Green, no irises
Hair: (as O'Rielly) Red, (as Mayhem) Green
Skin: (as Mayhem) Green

Strength Level: As an ordinary human being, Brigid O'Rielly had the normal human strength of a woman of her age, height, and weight, who engaged in moderate regular exercise. Mayhem's level of strength is as yet undetermined.

Known Superhuman Powers: Mayhem exudes a green, venomous gas from her pores that tends to surround her. If this gas enters another person's bloodstream, it will paralyze the person for an unknown amount of time. Hence, Mayhem attacks people by raking their skin with her talon-like fingernails so that the gas will enter their bloodstreams. Possibly some of her victims could be paralyzed for life due to the gas's effects.

The gas can also act like a truth serum, forcing a victim of Mayhem to tell her the truth.

Dagger's "light-knives" dissipate upon contact with this gas.

Mayhem can levitate herself and fly through unknown means. Her top speed is as yet unknown.

Since Mayhem technically "died", it is possible that her body functions differently now in other ways than those listed above. Exactly what those differences are remains to be seen.