Who is this idol and what happened to her?.

So for some years like literally 7-8 years, i've been looking for this MV, so like back then I didn't understand standard Japanese (hyojungo) so I forgot the title of this video, and honestly everytime asking about finding this video by describing by faint memory was also pretty bad as there are a ton of videos like this one.

But anyways one thing when after finding back this video was the main singer, while she is been much a kid in this and this MV was made back in 2016, who is she actually, was she popular back in 2016? (considering MV has 8.5 Mil views!!!!!!), does she still make music?.