King of Prism by Pretty Rhythm

Synopsis

The idol unit Over The Rainbow makes a successful debut, inspiring more students to join Edel Rose with aspirations of boy band stardom. As Hiro and his fellow students prepare for the prestigious Prism King Cup, a quadrennial competition, a new rival group, Schwarz Rose, emerges. The story follows the intense rivalry as aspiring idols vie for the title of Prism King, the ultimate prize for captivating female fans.