Kainé is a scantily dressed 17 year old swordswomen that is possessed by a shade called Tyrann. As a result of her upbringing and Tyrann’s occupation she has a natural tendency to act cold and cruel to others but has a shy and collected side that few ever see. Kainé is welcomed with open arms, loved, and respected by the people of Facade after she saved Fyra from wolves.
She was born in the Aerie and raised by her equally foul mouthed grandmother Kali, whom she dearly loved and from whom she inherited her attitude. One day when returning home Kainé encountered the shade Hook who pinned Kali down, sadistically enjoying Kainé’s despair. Kali was killed and Kainé was left mutilated but was saved when Tyrann fused with her. The ordeal with Hook left Kainé with a strong resentment for shades.
Kainé is half human with her left arm and leg (kept under wraps) being that of a shade. Living as an outcast, unwelcome in villages, befriended by few, possessed by a shade, and ridiculed for being a hermaphrodite has caused her to take a likening to clothes that emphasized feminine characteristics. She has grown accustomed to being alone and her natural shy nature is shattered by sudden outbursts and irrational displays of violent anger. Skilled with double swords, magic, and capable of using humanly impossible power gained through her boned with Tyrann, Kainé is a foe to be reckoned with.
Because of her boned with Tyrann she can understand the shades but refuses to believe their anything but evil. Tyrann even mockingly asks her if she's going to sympathize with the shade Gretel after hearing its vow to protect its fellow Shades. After exacting her revenge she joined Nier as a companion due to his kindness and having treated her as an equal. Kainé is relentlessly ridiculed and bitter with Grimoire Weiss who addresses her as the ‘Hussy’ while in contrast acts as a sisterly figure to Emil.
Depending on the ending Nier can kill Kainé and or sacrifice himself to restore Kainé’s humanity while completely erasing his existence as though he’d never existed.