User blog comment:B214/Volume 23 discussion blog/@comment-190.160.185.214-20170321211038/@comment-29963364-20170321212359

In the case with Ouryuu, I won't be sure until the actual volume is translated. But I have a speculation.

As I'm sure readers will remember from vol. 21, Suzaku Himejima (Akeno's cousin) possesses the Vermillion Bird of Fire, Suzaku. This Sacred Beast gives Suzaku the ability to create and control fire, and she can summon the Bird by shaping this fire into the Vermillion Bird itself.

Ouryuu possesses the Yellow Dragon of Earth, Ouryuu, which gives him the ability to tap into and control the "veins" natural ki from the land. He uses this ki to fight just like Sairaorg, by covering himself in Touki. Perhaps Ouryuu is able to do shape his Touki into the Yellow Dragon itself, which makes Ouryuu look like a "Human-Shaped Dragon."

It's basically a Touki version of Scale Mail.