Fans of South Korea’s wildly successful pop industry are used to the intrigue surrounding new groups, band members’ romances and their misbehaviour. Now a new source of K-pop drama has emerged from an unexpected quarter. On February 10th HYBE, an entertainment house which represents the genre’s biggest name, BTS, agreed to buy a 14.8% stake in SM Entertainment, a rival, from its founder and former chief producer, Lee Soo-man. Mr Lee,…