What is the relation between Shachi and Rize???

floppyamon:

(possibly adoptive) father and daughter:

he refers to her as his bitch daughter a few times…. but he cares

Also Rize and Shachi have the same coloring on their kagune (at least in he anime, which was made with Ishida’s influence to a degree, so I wonder if that plays into Rize’s uniqueness)