Housewarden of Heartslabyul. A serious-minded student who firmly upholds the rules written by the Queen of Hearts. While a top student, he is easily angered and just as strict with others as he is with himself.

Riddle is a young-looking, fair-skinned boy that is considerably shorter than a majority of his peers. His hair is a neutral red color, and is cut short in the back and a bit longer around his face. His bangs curve inward, and two prominent strands of hair on the top of his head fall forward and form a heart shape. His eyes are bluish-gray, and he is commonly seen with a stern look on his face.