One day、 Gojo Wataru impulsively downloads the app game “デーモンルーラー” (Demon Ruler). However, it turns out that the app allows him to summon and control demons. Together with a young witch who appears, Goro ventures into a parallel world and spends his days defeating demons as a means to relieve his daily stress! With each level-up, he unwittingly transforms into someone respected by those around him.