In the hyper-competitive market for zero-calorie beverages, companies have long sought the elusive formula that turns casual drinkers into brand devotees. Dong-A Otsuka, one of Korea’s prominent beverage manufacturers, appears to have found it in the rising trajectories of a young K-pop group. Dong-A Otsuka said Monday that sales of Narangd Cider Zero, its flagship zero-calorie carbonated soft drink, jumped 48 percent over a one-month period after the company appointed the rising K-pop quintet RESCENE as brand ambassadors. The increase — tracked from July 21 through Aug. 21 compared to the same period last year — was measured across major online retailers, Dong-A Otsuka’s direct-to-consumer digital storefront and ubiquitous convenience stores across Korea. Marketing experts point to the alignment of image and audience. RESCENE, a five-member act that debuted in early 2024, has rapidly cultivated a devoted following with a brand persona centered on authenticity and unvarnished appeal. That image appears to have resonated with health-conscious younger consumers who dominate the ze