How are Shoya and Maria related? In A Silent Voice, Shoya lives with his mom and a little girl named Maria. He refers to Maria as his little sister, but the two have different skin colors.

How are Shoya and Maria related?
It explain pretty well in manga and anime. She's not his sister, but she's his niece. Her mother is Shoya's sister and her father is a Brazilian. Maria's MAL page also mentioned


  Ishida's young niece who lives with Ishida and his family. Maria is half-Japanese from her mother's side and half-Brazilian from her father's side.


This is her father