Taira no Koremori, eldest son of the level-headed Taira heir Shigemori and grandson of clan leader Kiyomori, belongs to the Taira leadership lineage expected to sustain the family's political dominance.

During the Genpei War, Koremori commands Taira forces in significant battles. He achieves a notable victory prior to the Battle of Kurikara, temporarily boosting the clan's position. This success is overshadowed by his catastrophic defeat at Kurikara, where he flees overwhelmed by terror, described as wide-eyed and convinced of having escaped hell itself, reflecting profound trauma and the collapse of his military aspirations. This defeat marks a critical shift, drastically weakening the Taira. Though Koremori survives the Battle of Ichi-no-tani, rumors spread in the capital that he perished, causing family fears when defeated warriors' heads are paraded.

Koremori's personal life centers on deep familial bonds. He marries the daughter of Narichika, an opponent of the Taira secretly supported by Emperor Go-Shirakawa. They have at least two children, including a son named Rokudai. When the Taira flee Kyoto, his wife and children remain in the capital, forcibly separated from him. While taking refuge at Yashima, Koremori desperately seeks reunion, exchanging heartfelt letters expressing mutual longing and sorrow. His wife specifically worries about seeing his head among those paraded by the Minamoto, unaware of his survival.

Facing the clan's impending destruction and burdened by guilt and loss, Koremori seeks spiritual resolution. He takes Buddhist vows, formally entering religious life. This act of atonement precedes his final decision to commit suicide, concluding his story.