VTuber group name for the first-generation members of hololive ID (namely Ayunda Risu, Moona Hoshinova, and Airani Iofifteen). The name is a play on "Area 51" due to the general extraterrestrial theme of their characters (which is admittedly more subtle in Risu's case), combined with the fact that their birthdays are all on the 15th of different months.
Use this tag when:
The image/commentary mentions the words "ID gen 1 / ID1期生", or "Area 15".
The artist deliberately groups all 3 of the members (or their respective mascots) together.
