BT21 is a brand created in collaboration between the South Korean boy band BTS and the company Line Friends. The characters of BT21 were designed by the members of BTS themselves and each represents a member of the band.

The cute and unique characters have gained a massive fanbase worldwide and are available on a wide range of merchandise, including clothing, accessories, home goods, and more. BT21 also has its own animated series that showcases the adventures of the characters and is very popular with fans.

The BT21 brand has become a global phenomenon and serves as an example of the successful collaboration between musicians and companies in the entertainment industry.