The Dungeon of Black Company Vol. 10 (manga)

After getting flung into the rough-and-tumble past, Ninomiya Kinji has reunited with all his old friends and comrades. All of them except for one--the cute, effeminate mage named Ranga. No one in the past has heard of pop idol groups before, but for some reason, Ranga is committed to bringing his uniquely adorable, upbeat idol performances to a town full of hard-bitten adventurers. Ninomiya smells an opportunity. It's time to make Ranga and his friends into the world's number one musical act, and get an army of simping new customers in the bargain!