双葉社ジュニア文庫 王様ゲーム (Series) favorite_border

[DeepL Translation - needs review] Volume 1 Introduction: One day, all 32 members of a high school class receive a text message on their cell phones from someone who calls himself "The King". The orders gradually escalated... and finally the king's game with their lives on the line began!　The popular series has sold more than 6.5 million copies and is now available in a junior paperback edition!

(Translator: DeepL)