by conjecture (deduction)
(being a) fan of an entire music group (esp. idol group); not having a favorite member of a group
changing one's favorite (member of an idol group, anime character, etc.)
(doing) various things to support one's favourite member of a boy band, girl group, etc.
one's favourite member of an idol group
(being a) fan of a single member of a music group (esp. idol group)
fancam; video recording in which the camera follows a specific member of an idol group during a live performance