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.

Even after the show began, hundreds of ticketless fans braved the rain to listen to their idols outside the venue.

The concert leaned heavily on the band's new album Arirang, which folds the melody and mythology of Korea's folk music into the band's hyperactive, experimental pop sound.

All but one of the band's new songs featured in the setlist,

It opened with a lone hooded figure running onto the stage holding a red flare as fans chanted "BTS, BTS, BTS".

As scores of dancers poured into the stadium, the band strode confidently onto the stage before launching into Hooligan, an incendiary rap track full of chopped-up strings and clashing swords that  - somewhat ironically - featured RM calling for "a bigger mop".

That set the tone for the night, which concentrated on the tougher side of the BTS sound, favouring tracks like Mic Drop, Run BTS and FYA over the more melodic pop numbers that brought them international fame.

It gave the show a propulsive energy, with the septet sprinting up and down the compass-point catwalks that extended from the stage, surrounded by pyrotechnics, walls of flame and thousands of LED lights.

After an opening salvo of rap-centric tracks, Swim was moody and sultry, with flowing choreography that underscored its message of persevering in choppy waters.

There was also an unexpected outing for Not Today, a song dedicated to "all the underdogs in the world".

As the band sang about fighting injustice and corruption, they were surrounded by dancers in hockey masks, holding aloft fluorescent lights. It felt urgent and powerful - a marked departure from the frictionless fun of their last world tour.

Another major difference was the relative lack of choreography - with BTS concentrating more on firing up the crowd than the tightly-controlled dance moves fans have come to expect.

That may have been a result of the weather, but it also gave the concert an immediacy that more painstakingly scripted shows lack.

Towards the end of the show, there was even a moment where V and Jimin broke into an impromptu version of the dance routine for I Need U, much to the surprise and delight of their bandmates.

It was a little moment of connection (and, let's be honest, goofing around) that showcased the band's continued chemistry and affection for one another, even after all these years.

The main set ended with an extended version of Idol, the lead single from 2018's Love Yourself: Answer, during which the band climbed down from the stage and walked around the edges of the stadium as fans chanted the chorus from the rafters.

The encore was pure joy, with the English-language bops Dynamite and Butter cosying up to the nostalgic pop of 2019's Mikrokosmos.

All seven members took a moment to reflect on the show, with Jin calling it an "unforgettable moment" and Jungkook remarking "I made a good memory today".

"I'm soaked down to my underwear," laughed Jimin, "but the most important thing was getting to see you all.

"For four years, I couldn't see you and it was tough, but it's an honour that I got to see you again."

"More than anything, having all seven of us together is what matters most," added RM.

They wrapped up with another new song, Into The Sun, whose lyrical mantra - "I'll follow you into the sun" - is dedicated to their loyal fans.

The love was mutual.

"Their voices are so strong now and they looked amazing, wet hair and all," said one fan who'd tuned in to a live stream of the concert.

Others joked that they "should have paid for all three days" of the stream.

"My wallet is crying," joked another.

BTS are scheduled to play another two nights in Goyang - with 40,000 attendees at each show.

All of the concerts will also be broadcast on WeVerse, a social media platform owned by their record label, Big Hit / Hybe.

According to on-screen statistics during Thursday's show, more than four million fans paid to watch live video from the opening night, which would translate to $168m (£125m) in sales.

Figures like that explain why the Arirang tour is predicted to be one of the most lucrative concerts of all time - with some experts suggesting it could surpass the $2bn haul of Taylor Swift's epic Eras tour.

Either way, it will go down in history as the biggest ever tour by a South Korean band, with 85 dates in 34 cities worldwide.

BTS hit London in July, for two nights at the Tottenham Hotspur stadium.

Those will be the band's first UK concerts since 2019 - when they became the first K-Pop act to headline Wembley Stadium.

Main set

Encore

The R&B trio having been making waves this year with their latest hit, Leak It.

The singer says her card was used to buy designer clothes, telling the culprits "y'all going to jail".

The performance is part of efforts to help save the home the bard built north of Dumfries.

The event will be held on 27 June, with proceeds going to the charity Black Country Mental Health.

Telford College student Rory Black is being supported by Robbie Williams' producer, Guy Chambers.