Oousu no Miko

The first son of Emperor Keikou. As the heir to the throne he leads the expeditionary force against Kawakami Takeru. However in contrast to his younger brother Younger Prince Ousu he is timid and lacks decisiveness. Despite this Ousu admires him as an older brother and shows unwavering loyalty to him. Based on the mythological figure usu no Mikoto. mangapedia.com