Jakuun

Jakuun is one of the Hachiraishin, consisting of the so-called Gods who rule over the Shuuki.

Jakuun is a tall and slender humanoid Shuuki dressed with an elaborate trench coat with a flared up collar. In place of a head, she wore a black helmet.

Underneath her helmet and trench coat, she has the appearance of a young girl with long tied hear while wearing a leotard and a necktie.

From what little is shown, Jakuun is a polite and courteous individual towards fellow Hachiraishin, welcoming Shikoku and Jouryuu as she is the youngest of their group.

(Source: Mato Seihei no Slave Wiki)