ZEROBASEONE always had an expiry date. Formed through Mnet's Boys Planet as a temporary project group, the nine-member act was never designed to last – and on March 15, at KSPO DOME in Seoul, the clock ran out.

It was their sixth and final show at the venue across the HERE&NOW world tour, a run that took them through Bangkok, Saitama, Kuala Lumpur, Singapore, Taipei, Hong Kong, and Yokohama before returning home. With members Zhang Hao, Ricky, Kim Gyu-vin, and Han Yu-jin departing following the expiration of their contracts, the final Seoul date marked the close of a two-and-a-half year run that far exceeded what anyone could have reasonably expected.

Upon debuting, the group achieved million-seller status right out of the gate with their first mini album, Youth In the Shade – selling over two million copies and setting a sales record for a debut K-pop album. Since then, ZEROBASEONE have become a leader of K-pop’s fifth-gen, garnering legions of fans (known as ZEROSE) that have followed their journey over the years. With their legacy as we know it coming to an end, it’s a bittersweet ending for everyone involved.

During the sold-out concert, the group tried to make the most of the little time they had together. According to The Chosun Daily, the now-former members reflected on their time with ZEROBASEONE and how the inevitable end affected their performances during this final show. “As it’s our last performance, I had a lot on my mind and tried to focus to avoid mistakes,” Zhang Hao said. “I think I’ll shed tears instead of sweat today.” Referring to their performance of “NOW OR NEVER,” he also added, “Riding kickboards and seeing ZEROSE up close made me so happy,” and added, “It felt great to enjoy the moment together.”

Meanwhile, Ricky noted just how different this performance felt compared to the rest. “It was the first time I felt sad while performing ‘CRUSH,’” he said, referring to the track’s normally energetic and dynamic vibe. When you know it’s the end, everything just hits a little different.

But it was the concert’s final moments that were the most crushing to watch. As each member made their final curtain call – most of whom were already in tears – they exited through a doorway in the center of the stage one by one, allowing each one to have one final moment before the door closed on OT9 for good. Regardless of whether you’ve supported ZEROBASEONE since day one or since yesterday, it’s impossible not to feel the weight of the moment and just how final it is – once the door closes, there’s no going back.

K-pop is no stranger to temporary groups. WANNA ONE, I.O.I, IZ*ONE – all formed through competition shows, all built with a closing date written into the contract. It's a proven commercial model, but the human cost of it rarely gets examined. These aren't just colleagues. By the end, they're people who trained, performed, and built something real together – all while knowing, from day one, that it would end. That's a particular kind of grief, and the industry doesn't tend to leave much room for it. Idols are expected to put on a happy front, regardless of personal matters, but they shouldn’t be expected to endure it for the sake of their image.

Whether ZB1 as a quintet can hold the weight of what nine built is an open question – but then, so was everything else about this group from the beginning. Only time will tell how the next iteration of the group fares.