Soooooo people had been asking me, "dudette, what's behind Jubei's back? Seems that fluffy hair of her's had been covering some unraveled secrets.", which infact the audience is right.
Although it's like Nyu's but her's is her name marked at the back of her neck, Jubei almost occupied her back with that mark.
It's not some kind of rebel thing, it's to indicate some family insignia. Jubei's insignia is shaped almost like a lotus, she is wind element.
Mitsuaki, Ketsueki& Noriko has this one too, although from different parts of the body& different trademarks as well. Each insignia boost certain strengths of the siblings and somehow supports their defense mechanism.
It's not a painful thing, infact, even the siblings are proud to have these insignia with them.
Family pride baby~
FFFFF-..Reminds me of Shanoa from Castlevania crossed with Fairy Tail. TvT
Jubei (c) Me