SEOUL  –  BTS were battered by the elements as they kicked off their marathon world tour in Goyang Stadium, South Korea. The band, and their fans, were drenched by heavy downpours throughout the open-air show.  “It’s raining like crazy,” said V, splashing through puddles on the giant, 360-degree stage. Suga likened the venue to “a water park”, while Jimin said the conditions had left him “frustrated and stressed”. “But that’s not what’s important,” he told the audience. “What’s important is that you’re here with us.” The group gave it their all despite the weather, delivering a high-octane, pulse-quickening, complete with a 23-song setlist. After a four-year hiatus, during which the band’s members completed mandatory military service, BTS were fully re-energised and clearly happy to be back on stage. V even made a feature of the persistent precipitation, lying down on the rain-soaked stage and pretending to do the breast stroke, while performing an impromptu version of the band’s comeback single, Swim. “Watch out!” said the band’s leader RM, who recently sustained an ankle injury during rehearsals. “You might get hurt like me.” The 31-year-old, who performed from a stool during a promotional concert last month was back on his feet for the opening night of the world tour – which took place in his hometown. However, he was carried around the stadium on a makeshift throne during a “meet the audience” segment, suggesting his torn ligament hasn’t completely healed.  “It’s been three weeks [since the injury] so the doctor said I can perform,” he told fans from the stage. “It’s not that big of a deal. We just wanted to give it our all today.” The downpour didn’t seem to dampen fans’ spirits, either. Eager concert-goers arrived as early as 06:30 to reserve the best spots, taking selfies and sharing stories under a sea of umbrellas as queues snaked around the stadium.