OVA
Description
Kallen Stadtfeld is a central character from the anime Code Geass: Lelouch of the Rebellion. She is a young woman of mixed heritage, born to a Britannian father and a Japanese mother. While her legal name is Kallen Stadtfeld, which she uses in her daily life as a student, she strongly identifies with her Japanese roots and prefers to be called by her mother's maiden name, Kallen Kozuki, especially when participating in resistance activities. Her personal history is marked by tragedy and complexity. She was raised in Japan, then known as Area 11, and lived as a commoner before being officially acknowledged by her father's prestigious family. This recognition came after the Britannian invasion of Japan, yet it did not foster any loyalty to the Britannian Empire. Deeply affected by the death of her older brother, Naoto Kozuki, who was the leader of a resistance cell, Kallen took up his cause to fight for Japan's liberation.

Kallen leads a dual life that defines her public persona. At the Ashford Academy, she poses as a frail, delicate, and formal Britannian noblewoman, a facade she maintains to easily take leaves of absence and to hide her true allegiances. However, this reserved personality is an act. In reality, she is strong-willed, courageous, and fiercely passionate, with a short temper that often breaks through her school disguise. Her core motivation is to create a world where her Japanese mother, who willingly works as a maid in the Stadtfeld household to stay close to her daughter, can live happily and with dignity. This desire for a just world, combined with her brother's legacy, transforms her from a rebellious fighter into a disciplined soldier.

Within the Order of the Black Knights, the resistance group led by the masked revolutionary Zero, Kallen serves as the captain of the Zero Guard, the leader's personal escort unit. Her most significant role, however, is as the order's ace Knightmare Frame pilot. Piloting the advanced red Knightmare, the Guren Mk-II and its subsequent upgraded forms, the Guren Flight-Enabled Version and the Guren SEITEN Eight Elements, she is a formidable force on the battlefield. Her piloting skills are consistently depicted as being on par with the best, including the Britannian Knight of Round, Suzaku Kururugi. Her combat abilities are a key asset to the Black Knights, making her one of their most invaluable members.

Her key relationships are central to her character development. She holds a profound admiration for Zero, initially seeing him as a symbol of hope for Japan. Her loyalty to him is absolute, and she is one of the few members aware of his true identity as Lelouch Lamperouge and his Geass power. This knowledge creates a complex dynamic; she struggles with feelings of betrayal concerning whether his power was used to control her, but ultimately accepts that her loyalty is her own. Over the course of the second season, her feelings for Lelouch grow deeper, evolving into love. This is tested when she sees him seemingly become a tyrant, leading to her participation in the Black Knights' betrayal of him. Nevertheless, during the Zero Requiem event, she is shown to be one of the first to understand his true intentions, mourning his death while recognizing the peace he sacrificed himself to achieve.

Throughout the series, Kallen undergoes considerable development from an initially hot-headed resistance fighter driven by anger into a more mature and thoughtful soldier. A turning point is her confrontation with her mother's suffering, which refines her motivation from mere revenge to the constructive goal of building a better future. Her relationship with Lelouch also matures her, forcing her to reconcile her personal feelings with her duties as a revolutionary. Her notable abilities extend beyond piloting. She is also a capable hand-to-hand combatant and, despite her frequent absences, a top student at the prestigious Ashford Academy, showcasing a sharp intellect that she often downplays.