Her character arc can be summarized as thus: she transforms from an emotional, somewhat prejudice, untrusting girl in a tawdry rebellion into a confident, capable fighter with a much stronger sense of justice and morality, willing to put aside her feelings and interests to protect those she loves and cares about.At Ashford Academy, Kallen was forced to hide her identity in order to avoid suspicion, which caused her to change her hairstyle and her true personality.Despite her tough attitude, Kallen is actually quite sensitive, compassive and truly gentle, however after the death of her brother she doesn't show this side much any more.
Her mother is an Eleven who stayed with her children for most of their lives. So please, keep fooling us until you no longer can! You have to live up to the dreams you once gave us all!Her brother, Naoto Kōzuki (紅月ナオト, Kōzuki Naoto), with whom she had a deep connection, was a former leader of a resistance organization before his death.After his death, Kallen became a member of the same guerilla resistance group against Britannia, which would later be reformed into the Order of the Black Knights by Lelouch Lamperouge several years later. Kōzuki to formally adopt Kallen into his household as his heir.Kallen is a young woman who has a slim yet strong build, and fair skin.Her most distinguishing features are her big blue eyes and her red hair, which she had combed down at school but spiked up when fighting or in her own privacy.Her relationship with her father, both before and after Britannia took over Japan, is never revealed, though she has referred to him as "dad" on one occasion, implying that their relationship is (or at least was) probably positive.While being both Japanese and Britannian, Kallen had the ability to live a normal life.Other times, Kallen is seen wearing a standard Black Knights uniform. While at important reunions or during her brief time as a prisoner, she wore a yellow, fashionable dress to an elegant blue dress.Kallen is a strong-willed, determined, loyal and brave individual who also can be quite short-tempered, forceful and somewhat impulsive.