Mr. X

Mr. X (Japanese: ミスター X Misutā X), occasionally referred to as simply X, is one of the students of Midnight Horror School. During the day, they are a paper bag.

Appearance
Mr. X's head is completely covered by what seems to be, as shown in one of the earlier episodes, an endless amount of paper bags. The only part of their face visible is their eyes, which are a deep indigo color. The stripes on their shirt are green and blue, with a yellow X decorating the middle.

Personality
Mr. X is a mysterious figure, who never speaks other than occasional laughter. Because they don't talk, not much is known about them by the other students of the school, which has occasionally been made into the main plot point in a few of the episodes.

Trivia

 * Although their name uses the male honorific "Mr.," Mr. X's gender is non-binary or genderless.
 * According to a Tweet, Mr. X is named after the criminal character in the Scotland Yard board game with the same name.