柊家の一員で、日本帝鬼軍少将の肩書きを持つ実力者。荒々しく攻撃的な性格をしている。兄の暮人に対して強いコンプレックスを抱いており、密かに下剋上の念を燃やしている。
Seishiro is a member of the Hiragi Family, and a person of influence as a Major General of the Japanese Imperial Demon Army. He is rude and has an offensive personality. Has a strong complex against his older brother Kureto, and secretly planning to outwit his brother one day.
