Leila Malcal is the deuteragonist of Code Geass: Akito the Exiled and serves as the commander of the wZERO Unit, a special forces unit within the European Union Army composed of Japanese teenagers. She is a former Britannian aristocrat by birth, born as Leila Breisgau to parents who defected from the Britannian Empire in pursuit of freedom and democratic ideals. Her father, Bradow von Breisgau, was a politician who was assassinated during a rally when Leila was six years old. In the ensuing chaos, her mother Claudia was also killed in an attack on their car. Fleeing into snowy woods, Leila fell into a frozen pond and was rescued by a woman she later remembered only as the Witch of the Forest, who offered her a Geass contract but gave her the choice not to use it, allowing the power to fade if left unused until adulthood. Leila forgot this encounter over time. She was subsequently adopted by the Malcal family, a wealthy and influential Europian conglomerate, and was betrothed to their third son, Ioan. She befriended Anna Clément during her school years, skipped several grades, graduated from university, and chose to join the military.

Leila exhibits a polite and feminine demeanor shaped by her refined upbringing, but her military training strongly influences her mindset and actions even in social settings. She is exceptionally gentle yet firm and resolute toward her subordinates and comrades. She holds no prejudice against the Japanese and actively corrects those who refer to them as Elevens. As an officer, she is deeply committed to her country but struggles with the reality that her unit sends young Japanese men into dangerous battles. To counterbalance this, she seeks ways to ensure their safe return and does not hesitate to fight alongside them. Her core motivation stems from a sincere belief that if people could truly understand one anothers feelings, conflict would disappear. This desire to connect with others ultimately drives her actions and the nature of her Geass.

In the story, Leila initially serves as an adjutant to Lieutenant Colonel Pierre Anou. She plans Operation Alpha to rescue a surrounded regiment, but confronts Anou when he makes last-minute changes that would send Japanese soldiers into suicide attacks, ultimately removing him from command. After the operations success, General Gene Smilas promotes her to Lieutenant Colonel and gives her direct command of the wZERO Unit, which includes Akito Hyuga, Ryo Sayama, Yukiya Naruse, and Ayano Kosaka as the core Wyvern Squad. Throughout the series, she leads her unit through dangerous missions, including behind-enemy-lines operations, a period of being stranded with Romani women, and a final confrontation with the antagonist Shin Hyuga Shaing, Akitos older brother. When Shin attempts to kill her with his own Geass, Leilas dormant power activates for the first time, causing him pain through backlash. She later uses her awakened Geass to confront Shin with visions of the dead, contributing to his defeat.

Leilas key relationship is with Akito Hyuga, her subordinate pilot. Over the course of the story, they gradually bond through shared trauma and mutual understanding, with Akito revealing his hatred and fear of his brother and his past, while Leila shares her own history. Their relationship develops into a close personal one, and after the wars conclusion and the European Armys transition into a republic, the Wyvern Squad retires and Leila and Akito begin a relationship. She also builds trust with the other Wyvern members Ryo, Yukiya, and Ayano, initially distrustful Japanese soldiers whom she persuades to join her unit and whom she treats with respect and care. Her relationships with authority figures like Anou are confrontational, while Gene Smilas supports her promotion and command. Her connection to C.C., the immortal witch who granted her Geass, remains indirect and largely forgotten until her powers awaken.

Leila undergoes significant development from a dutiful but frustrated officer constrained by superiors who disregard her concerns, to a decisive commander who takes direct action to protect her unit. Her personal growth involves moving from forgetting her childhood trauma and Geass contract to confronting both when her powers surface, ultimately using her ability not as a weapon but as a tool for understanding. By the end, she chooses to leave military service and pursue a life with Akito.

Leila possesses notable abilities beyond her command skills. She holds a black belt in Aikido, a Japanese martial art, and combined with her military training, she is a highly skilled hand-to-hand combatant capable of subduing armed and larger opponents with ease. Her Geass, known as the Choice of Possibilities, manifests through her left eye with an unusual blue color. It grants her the ability to perceive visions of possibilities, pulling her away from reality to allow honest encounters with others, enabling her to observe others pasts and understand their true feelings, and to share thoughts, memories, and emotions between individuals without words. It can also counter other Geass effects, inflicting pain on those who use their Geass against her. Because Leila forgot her contract and never consciously activated her power for years, the ability was considered a Geass Fragment by the Caretaker of Spacetime, and it only fully manifested during the climax of the story.