Ryoko Balta is the princess of the Balta Guild or heiress. She was offered to go back to the state of Balta but declined because she said she would serve Seina for the rest of her days.
She is age 19
She can shapeshift into Erma
She is a fan among the males in G.P. probably a few females also but never mentions.
She is very jealous person same as Amane Kiriko and Neiju.
an extended description!