This roleplay character belongs to Antonia and can be found here
“I don't care particulary much about what happens to you.” — Cassia to Sansa Stark
Cassia Bolton is the legitimized bastard daughter of Roose Bolton and an unnamed woman. The half-sister to Ramsay Bolton. Many are often fooled by her innocent looks, but in truth she's just as ruthless as her half-brother Ramsay.
She is portrayed by actress Camren Bicondova in season four and five of Game of Thrones.