As said in the post, it's BVNDITBUL, with the meaning of "BVNDIT Be Ur Light".
It follows the trend of the group's name, of abbreviating a phrase (BVNDIT means Be Ambitious Nd Do IT).
Apparently the Hangul of the fandom name also means Firefly in Korean, fitting well with the meaning...
The chosen fandom name is "Young One"
The only problem, as immediately noticed, is that Tiffany Young has already chosen the name Young Ones for her own fans
Both fandom names are exactly the same in Korean, "영원" meaning "forever" in English
Obviously, fans being fans, this is already a...