It feels like the general age range for female idols has expanded over the past few years, both for whole groups and just individual members scattered around.

Especially if you include the groups that use it directly as part of their gimmick, like OBACHAAAN and the AIP Around 40 Idol Project.

I didn’t realize that the members of Negicco and predia were that old, so yeah, they definitely qualify as adult idols. Good call!

That said, do you not consider predia and Negicco to be adult idols? I can think of a few other groups that might fit the bill too, though mostly because of age.