I guess it's an online band created by BTS, Big Hit Entertainment, and LINE FRIENDS. Each BTS member has one character that represents themselves. BT21 was also made as a puzzle game called Puzzle Star BT21.
BT21 was created by BTS.
by taehyung's romantic wife November 3, 2018
BT21 are a Line production made by BTS. The line BT21 consists of Jin's character: RJ. Suga's character: Shooky. J-Hope's character: Mang. RM's character: Koya. Jimin's character: Chimmy. V's character: Tata. Jungkook's character: Cooky. And a bonus character, Van. All characters are designed based on each BTS members' drawings which you can see them creating in a YouTube series about it where you can see the process of drawing them. BT21 has its own Twitter and Instagram account. BT21 is used in a lot of designs for Line, like plushies, dolls, headbands and more.
BTS fan: I got a new BT21 plushie!
Someone: What is BT21?
BTS fan: BT21 is adorable characters for Line designed by BTS!
Someone: What is BT21?
BTS fan: BT21 is adorable characters for Line designed by BTS!
by ARMY0505 September 28, 2019