"I'm not sure we'll see another Sonny at Tottenham," Kevin Wimmer, Son Heung-min's close friend and former Spurs team-mate, tells BBC Sport.
"To be at one club - especially one as big as Spurs - for 10 years in this day and age is a very special achievement."
After 454 appearances and 173 goals, Son is moving to pastures new a decade after Mauricio Pochettino brought him to north London from Bayer Leverkusen.
The South Korea forward was the most expensive Asian signing in the Premier League when the then 23-year-old arrived in 2015 in a deal reportedly worth £22.5m.
Now aged 33, Son leaves three months after writing his name in Spurs folklore by helping the team to victory over Manchester United in the Europa League final to end the club's 17-year wait for a major trophy.
"We love players who give so much to this club," Micky Hazard, an FA Cup (1982) and Uefa Cup (1984) winner with Spurs, says.
"Sonny will always be worshipped in these parts."
On the pitch, Son will be remembered by Spurs fans for his searing pace and outstanding moments like his wonderful solo goal in 2019, when Tottenham's number seven was too quick for Burnley as he ran all the way from the edge of his own penalty area, dodging tackle after tackle, before slotting past Nick Pope.
Off it, he will be remembered by team-mates for his incredible gestures.
Son paid the bill when he took the team out for a Korean barbecue during Tottenham's pre-season tour of South Korea in 2022 before giving the whole travelling party personal gifts to mark their visit to his home country.
"When he first arrived, I didn't know much about him," Hazard tells BBC Sport.
"Ten years on, he's leaving a Spurs legend."
Son had already rejected Pochettino before joining the Argentine at Tottenham and embarking on a 10-year love affair with Spurs.
In 2013, Pochettino had just taken charge of Southampton when he met with the then 20-year-old - who was already making a name for himself with Hamburg - his father, Son Woong-jung, and his agent.
Pochettino tried to convince Son that Saints, then in the Premier League, would be the ideal place to continue his football education, but the player moved to Bayer Leverkusen instead where he spent two years before finally linking up with Pochettino, who had been appointed Spurs boss 15 months earlier.
Yet he struggled to settle in his early days in London and asked to leave, external less than a year into a five-year contract before deciding to stay and fight for his place.
A decade after arriving, Son leaves with a Europa League winners' medal - as well as a sackful of individual prizes, including the 2021-22 Premier League Golden Boot, which he shared with Liverpool's Mohamed Salah after both players scored 23 times, and the Fifa Puskas award (presented to the scorer of the "most beautiful" goal of the calendar year) for that run and finish against Burnley in 2019.
"Everything about that goal is a symbol of how he plays the game," adds Hazard.
There have been crushing disappointments too, like defeat by Liverpool in the 2019 Champions League final, and losing to Manchester City in the 2021 EFL Cup final.
In 2019, he apologised for his tackle on Andre Gomes which left the Everton midfielder with a horrific ankle injury and which resulted in the visibly upset Son being sent off.
Yet the individual awards have continued to flow.
Four Premier League player of the month prizes, two-time winner of goal of the month, three-time Tottenham player of the year... the list goes on.
A fierce competitor on the pitch, Spurs supporters have warmed to Son's 'Mr Nice Guy' image off it.
After Tottenham defeated West Ham in the EFL Cup in 2021, a young fan managed to get on the pitch and ran towards the player before being surrounded by stewards.
The boy was being escorted away when Son caught up with him, took off his shirt, and handed it to the youngster.
Son is big news in South Korea.
Actually, that's not quite true. Son is huge news.
"There has been research about who has the best brand value among all South Korean people, and Son is almost always in top three along with top K-pop stars like BTS and Blackpink," adds Sungmo Lee.
"One of the reasons for that is South Korean people regard him as the national treasure and pride of the country."
In South Korea, there are regular television programmes that are simply compilations of Son's best goals and assists, while a Son icon appears above the scoreboard to denote he is playing during live broadcasts of Tottenham matches in the country.
His face beams from giant billboards advertising anything from clothes to ice cream, and Son's picture has also appeared on the side of the capital's buses promoting tourism.
In Son's hometown of Chuncheon, about 50 miles from Seoul and where a football academy has been set up by the player and his family, there is a huge mural in his honour.
England right-back Kyle Walker, who played for Tottenham between 2009-2017, recalls a promotional visit to Seoul with Son soon after Spurs finished runners-up to Premier League champions Chelsea at the end of 2016-17.
Former Austria centre-back Wimmer and Wales defender Ben Davies joined the trip to meet sponsors and a thriving Spurs fanbase, which had grown significantly since Son signed.
"I've never seen anything like it," Walker, who spent eight years in north London before joining Manchester City in 2017, said on his 'You'll Never Beat Kyle Walker' podcast.
"We'd do an appearance and then we'd have to use decoy vehicles to get away because fans would try and stop the traffic. They all wanted to catch a glimpse of Sonny.
"They'd come back to the hotel where we were staying and all night they'd sit outside. It was incredible.
"I've seen it before to a certain degree with Wayne Rooney, Frank Lampard and David Beckham. But it was nothing compared to Sonny."
Wimmer, who has stayed in touch with Son since leaving Spurs in 2017, likened it to "being in the company of a rock star".
"I was always joking with him about this," he says.
"I said: 'You are the most famous guy in South Korea', but he was like: 'No, no, it's not so special'."
Former Austria defender Wimmer had arrived at White Hart Lane from Cologne in the summer of 2015, three months before Son.
"I knew of him because, like me, he was playing in the Bundesliga," adds Wimmer.
The pair struck up an instant friendship in London.
In their early days at Tottenham, they would often speak German together while they improved their English.
After a win at Southampton in 2016, Son and Wimmer interviewed one another - in English - for Spurs TV.
"Kev, why are you my best friend?" asks Son.
Wimmer replies: "Because you are a wonderful guy, an honest guy. It's always funny with you and I hope we stay together for many more years here."
Within a year, Wimmer had been sold to Stoke for £18m. Son stayed to become a Spurs great.
In the space of two years Spurs have lost Harry Kane - their all-time top scorer with 280 goals in 435 appearances - and now Son.
Following Kane's departure to Bayern Munich in August 2023, Son stepped up by scoring 17 goals and adding 10 assists in 35 Premier League appearances as Spurs finished fifth in 2023-24.
However, Son scored just seven goals and provided nine assists in his 30 Premier League appearances in 2024-25. He also endured an injury-hit end to the season and was restricted to a 67th-minute substitute appearance in the Europa League final.
Four days after beating Manchester United in a European final, great names from Tottenham's past formed a guard of honour for soon-to-depart manager Ange Postecoglou's side before the home game with Brighton on the final day of the season.
Ossie Ardiles, Pat Jennings, Keith Burkinshaw and Martin Chivers were among those who lined up on the pitch - along with Hazard.
"Sonny came up to each and every one of us, shook our hands, and said: 'Now I'm a legend'," adds former Spurs midfielder Hazard.
"Despite everything he achieved in 10 years at Spurs, he still didn't believe he was a legend until he won a trophy. I think there is something special about that, something beautiful. It says so much about his character."
Wimmer, who now plays for Slovan Bratislava in Slovakia, messaged his friend immediately after the final in Bilbao to congratulate him on helping Spurs win a first major European trophy since 1984.
"Out of hundreds of messages he received that night, Sonny still took time to get back to me," he says. "I was so pleased Sonny was finally able to get his hands on a trophy."
Spurs are supported by 12 million - almost one in four - South Koreans, according to research commissioned by AIA, the Asia-based insurance firm which is the club's shirt-front sponsor.
"Son is a pride of whole nation," says Sungmo Lee.
"He already proved himself to win the Golden Boot in the Premier League, which was regarded as impossible for an Asian player."
Son made front page news in 2020 when he travelled back to his home country for compulsory national service.
The player spent three weeks with the South Korean Military Corps, where he finished among the top five performers.
"It was big news and one of the reasons why Korean people love him even more," adds Sungmo Lee. "The training included firing guns. He got the award for being among the best trainees out of 157 he trained with."
Will Son's departure hit Tottenham's revenue streams?
On matchdays at Tottenham Hotspur Stadium, up to 700 Son shirts are sold - the most of any player - because of the increasing number of fans travelling from South Korea to watch their hero in action.
"They tend to be wealthy fans with disposable income," football finance expert Kieran Maguire tells BBC Sport. "They don't just buy one Son shirt, they're coming away with two carrier bags full of stuff with Son's name on the back."
Maguire believes there could be a "small" impact on Tottenham's finances now Son has announced he is leaving.
"While it will be a blow for Spurs fans in terms of memories because Son has been a magnificent player for them, the difference between finishing 16th and 17th in the table (Spurs finished 17th last season) is £3.5m.
"Over the course of the season, that's more important than shirt sales from one player."
So what does the future look like for Son, who is in advanced negotiations with Major League Soccer side Los Angeles FC.
"On several occasions, including his interview with the Korean media in 2024, he has said he won't be a football manager and won't be staying in football after his retirement," adds Sungmo Lee.
"He also said, for that reason, he wishes to continue his football career for as long as possible."
Whatever he decides to do when he stops playing, Son's memory will live on at Tottenham and beyond.
"No-one will ever forget Sonny," adds Wimmer.
