Kaname Ohgi is introduced as the leader of a small Japanese resistance cell. Before Japan’s subjugation by the Britannian Empire, he was a teacher, a profession he felt was a better fit for his skills. He took command of the resistance group following the death of his close friend, Naoto Kozuki, though he was self-aware enough to admit that leadership was not his strong suit. Upon the appearance of the masked revolutionary Zero, Ohgi quickly recognized the young man’s strategic brilliance and willingly ceded leadership of his group, which became the foundation for the larger organization known as the Order of the Black Knights.

Ohgi is defined by a deep care for the well-being of others, which serves as both his greatest strength and a point of manipulation. He is a compassionate and honorable individual who values human life, refusing to kill an enemy in cold blood or use the memory-altering drug Refrain to extract information. This compassion is most clearly seen when he finds the Britannian soldier Villetta Nu gravely wounded. Despite her being the enemy, he nurses her back to health and protects her when she loses her memory, even giving her the name Chigusa. The two grow close over time, and he genuinely hopes for a peaceful resolution between Japan and Britannia, as proposed by Princess Euphemia. However, the resulting massacre shatters his faith in reconciliation, leaving him enraged and viewing the Britannians as an evil force.

Within the Black Knights, Ohgi serves as the Deputy Commander and later the General Secretary. While he lacks the tactical genius of Zero, his level-headed and approachable nature makes him a stable and respected figure among the rank-and-file members, who see him as a trustworthy and humane leader. His loyalty to Zero, however, is built on the belief that Zero fights for the liberation of Japan and the protection of the Japanese people. As the series progresses into the second season, this conviction is tested. The revelation that Zero might be using the Black Knights as pawns, combined with his romantic feelings for Villetta Nu, creates a deep conflict within him. He is torn between his duty to the organization and his growing distrust of their enigmatic leader.

Ohgi’s role becomes pivotal during the climax when he is presented with evidence that Zero is actually Lelouch vi Britannia, a prince of the enemy empire who possesses the power of Geass to compel obedience. Believing he must act to free Japan from what he sees as a manipulative tyrant, Ohgi leads the betrayal of Zero. He insists that if they betray Zero, it must be in exchange for the tangible return of Japanese independence, a demand driven by his guilt over the act of betrayal itself. After Zero is seemingly eliminated, Ohgi continues to lead the Black Knights in their final confrontations against Emperor Lelouch. His relationship with Villetta Nu culminates in her pregnancy, leading him to remove her from the front lines to protect their new family.

Following the Zero Requiem, Ohgi’s development comes full circle. He marries Villetta Nu and is later elected as the Prime Minister of the revived United States of Japan, finally holding the political leadership he never sought. He resigns from this post sometime later. When Lelouch is revived, Ohgi is confronted with his past betrayal and attempts to take his own life as punishment, but Lelouch forgives him, stating that the past is in the past. This act releases Ohgi from his guilt, allowing him to continue his life with his family. Physically, Ohgi is a tall man with dark brown hair and gray eyes, notable for the red headband he always wears. As a pilot, he is competent enough to operate a Knightmare Frame in combat, though he is not an ace on the level of Kallen Kozuki. His primary ability lies in organization and management, serving as the ethical core and administrative anchor for the massive military organization the Black Knights become.