Shiro

Shiro is one of Ziel's supposed servants, but she insists that they are "friends".

Personality
Due to having a strange condition that makes him unable to talk, he communicates with people with facial expressions or his own magic.

At first, he seems to be emotionless and mute but is in fact very kindhearted to his friends and other people, specifically people like Ziel and Zero. When with these people, he is much more expressive. When with others, however, he tends to restrain his emotions.

Trivia

 * It was Ziel who taught him how to use Letter Magic so it makes it easier for him to communicate with people.