Bloom Into Ayumu

"Why do you go where I can't follow?"

Despite performing solo, Karin isn't alone because she has everyone in the club backing her up.

Performing with my true self.

No wonder this girl is so sleepy.

Now that's what I call a face reveal!

Listen Karin, you're the last holdout in this season. You might as well join the club.

Ai being one of the first people to be on board with being a solo idol makes sense.