Talk:Karaka/@comment-103.21.170.130-20161015093046/@comment-25346948-20161015094514

As mentionned in the Notes and Trivia, there is a double explanation:
 * Story telling device: new characters appear at the same moment, SIU did not want to introduce too many faces, hence Karaka wears a mask so that he would remain mysterious.
 * In universe: because Jinsung gets on his nerves.

Source and translation.