Emperor Chuai

A.k.a. Prince Tarashi Naka

Pages 37-38 of Aoki's 'Ancient Myths':

Chuai's minister "Takeshi-uchi Sukune (Little Brother the Brave)" was Katsuragi leader. The Katsuragi were famous for their involvement in Korean-Japanese communication. Chuai did not wish to go across the sea to Korea (Jingu's plan), but rather wished to go to Kyushu. The god that told Jingu to travel to Korea became angry with the disobedient Chuai, who subsequently died. "In order to maintain their supremacy, it was necessary for the Katsuragi to have the Yamato confederacy involved in the affairs on the Korean peninsula."

Therefore, this may be seen as a poetically described assassination.