Betty Ross is the daughter and only daughter General Thaddeus "Thunderbolt" Ross who ran a Gamma-Bomb Testing base in New Mexico where Betty visited in adulthood and fell in-love with the base's chief scientist Dr. Bruce Banner, a man who Ross hated for being a "weakling". Eventually Bruce turned into the Hulk which caused Betty's father to be obsessed with hunting him down and killing him, becoming one of Hulk's arch-enemies. Hulk and Betty had a long on-again-off-again relationship due to Bruce's alter-ego which caused her to develop emotional-health issues and identity problems.
Due to having been frequently exposed to Gamma Radiation from Hulk, her father, Hulk's other enemies and even having once been turned into a Gamma monster called "The Harpy", Betty seemingly died of radiation-poisoning only to be resurrected by M.O.D.O.K. and the Leader by way of the same process which transformed her father into the Red Hulk. Unlike with her father, Red She-Hulk was a separate personality in Betty's mind who personified Betty's dark-side and was violent, sadistic, and cruel to all who came in her way, friend or foe. Also unlike the Hulk or She-Hulk she has yellow saliva which is acidic and can be used as a weapons by means of spitting. Split between her two personalities, Betty distanced herself from others and Bruce and stayed in the company of an android modelled after her divorced husband Glenn Talbot in-order to monitor her changing personalities.
- Betty Ross is portrayed by Liv Tyler in the Marvel Cinematic Universe who also played Arwen Evenstar in The Lord of the Rings trilogy.