Since 2023, Seoul-based indie rockers wave_to_earth have sold out two separate U.S. tours — a rarity for K-pop groups, much less K-indie rock outfits. Their Hammerstein Ballroom show in New York City was the penultimate stop of their latest 30-date trek that saw them playing rooms just one tier size below arenas. “But the data can’t capture the pure intensity of their fandom,” Steffanee Wang writes, “which I witness firsthand as I watch hordes of young women (and guys) scream and cry for an hour straight.” It wouldn’t be totally inaccurate to say that wave to earth have become the somewhat unofficial ambassadors of the rapidly growing South Korean indie rock scene. Since breaking out in 2020 with “Seasons,” which soundtracked over a million videos on TikTok, their career has gone turbo mode, sending them on back-to-back treks throughout Europe and the U.S. “Our music is famous, but we are not famous, personally,” guitarist Daniel Kim says, modestly. John Cha adds, “[Our fans] don’t...