Board Thread:WARNING ALL USERS False Info\Spoilers/@comment-24458290-20140218141056/@comment-2187922-20140219145835

I think that it might be a physical manifestation of her kitsune powers and everytime she breaks one, she can summon the oni, but it costs her maybe 10 years of her life span? So like, every 10 years, she loses another to age. Like, she started off with 9, but she lost 3 due to age, and she broke like, 4 more to summon the oni. So if she has 2 left, that means she'll only live for 20 more years.

I mean, it would explain why Mr. Yukimura looked really upset as she broke two more, but it meant that he would only have her alive for 20 more years.