Brandy is a feline that has natural agility, panoramic vision, has good smell and hearing, night vision, and she has unique acrobatic abilities. Her whiskers can also pick up vibrations. Her combat skill is infamous as she can learn any combat move by watching it even once, not having to worry about the stress thanks to her neglect of such. She can even tolerate large amounts of pain and keep fighting, mostly because of her mentality. Despite her insanity, she is a strategic fighter who knows how to use whatever weapon she comes across, stealing whatever weapon she wishes and using it against her opponents.
But what makes her very dangerous is when she always carries red brandy in a liquor bottle. With just a sip, her mentality gets more unstable for the next 12 hours, and whenever that happens, nobody she deems a threat has survived or avoided a slight injury. Drinking alcohol makes her so feral, her mentality is increased ten fold, and given she can carry and steal weapons expertly, this can be catastrophic to her opponents. But she remains this way after victory, and thus peers such as her sister (except when she is under the same condition), and other Undergrounders have to restrain her until the effects wore off.
While Red has been diagnosed with schizophrenia, she didn't start out as the complete monster she and her adopted sister are today. Like all Undergrounders, the Corruptus radiation had fun playing with both sisters' mental disorders, and made them permanently unorthodox cuss factories who think that profanity and violence is a grand form of self-expression. They are not afraid to harm or kill others if they cross them, but sometimes, even with the Corruptus radiation, they are not complete monsters as they can easily be tamed if careful and nice enough, but it is still quite difficult to play to their soft sides as there is hardly any left.
Red herself is the most mentally-unstable of the sisters. She takes joy in violence and blood, and has sometimes been seen tasting the blood of her enemies, or even licking the blood off her bloody punched lips. She fights mercilessly, and the only ones keeping her in line is her mentally-balanced sister and Underground peers. But once Undergrounders become obsolete, the two are left on their own, and drinking alcohol together to fight with equal strength against opponents is no longer an option since there are no supporters to keep them from doing additional damage.