Eldest son of Taira no Shigemori and grandson of Kiyomori. His beauty earned him the epithet "the reborn Hikaru Genji." In 1180, sent to suppress Yoritomo's rebellion, he retreated without fighting at the Battle of Fujikawa, startled by the sound of water birds. In 1183, he marched against Kiso Yoshinaka in the north but suffered a catastrophic defeat at the Battle of Kurikara Pass, where Yoshinaka's fire-ox stratagem destroyed his army. This loss directly triggered the Taira's flight from the capital. He wandered the western provinces with the clan but in 1184 left Yashima and drowned himself off Nachi. He is portrayed in "The Tale of the Heike" as a tragic Taira prince combining beauty and misfortune.

A refined aristocratic figure blessed with beauty but lacking decisiveness as a commander. His delicate temperament was suited to the elegance of the capital, not the pressures of the battlefield.

The disaster at Kurikara Pass became a turning point in the Taira's downfall. Koremori's tragedy in "The Tale of the Heike" embodies the pathos of a warrior aristocrat and continues to evoke sympathy.