As of my last update in September 2021, BTS holds one of the largest and most dedicated fandoms in the K-Pop world. The fandom, known as the "ARMY," has grown exponentially alongside the group's global success. BTS's ARMY is known for their passionate support, active engagement on social media, and their role in contributing to the group's record-breaking achievements.
The ARMY's dedication is evident in their involvement in streaming music, purchasing albums, attending concerts, and participating in various fan projects to support BTS. Their strong presence on social media platforms, including Twitter, TikTok, and fan communities, has helped BTS maintain their popularity and break new records in terms of views, streams, and chart placements.
It's important to note that the popularity landscape in K-Pop can change rapidly, and other groups like EXO, BLACKPINK, TWICE, and more also have significant and devoted fanbases. The size and influence of fandoms can vary based on factors like group activities, releases, and interactions with fans. For the most up-to-date information on the biggest fandoms in the K-Pop world, it's recommended to check official sources, social media metrics, and music charts.