Born in 1178, son of Emperor Takakura and Taira no Tokuko (later Kenreimon-in), and maternal grandson of Taira no Kiyomori. He was enthroned at age 1 and formally crowned in 1180 at age 3 by modern count. That same year, the Minamoto began rising across the country in response to Prince Mochihito's decree, and the Genpei War began. In 1183, when Kiso Yoshinaka pressed toward Kyoto, the Taira fled the capital with the young emperor in tow, wandering for two years through western Japan (Kyushu, Nagato, Sanuki). At the final battle of Dan-no-ura in 1185, the Taira were annihilated. Cornered, the Taira women drowned themselves with their children. Antoku's grandmother Nii no Ama (Taira no Tokiko) lifted the young emperor in her arms and told him "There is a capital beneath the waves too," then leaped into the sea. He was 8 years old by the Japanese count (6 by modern reckoning). The sacred sword Kusanagi, one of the three imperial regalia, sank with him and has never been recovered. He is enshrined at Akama Shrine in Shimonoseki, where the graves of the Taira also stand.

Too young to rule by his own will, yet his tragic end became the most poignant symbol of the Taira clan's downfall, mourned across centuries of Japanese literature.

The youngest emperor to die in Japanese history. Enshrined at Akama Shrine in Shimonoseki. Inspired legends including the Heike crabs. The ultimate tragic symbol of the Heike tale.