User blog comment:Godisme/The Six Fullbringers/@comment-1393830-20110115195036/@comment-1268838-20110116012736

I am interested in this as well. By the sounds of it, their kind have sought out other Shinigami-Human hybrids (Substitutes?) in the past so they could give them their powers. So where are those presumably stronger Shinigami?

My pet theory at the moment is that Ginjo himself is actually one of those very Shinigami, and that the Fullbring powers he currently has were given to him.