Did author state this is Ranko? Cause she doesn't look like Ranko at all. Pure Formidable...

the author provided tags on pixiv include Ranko's tag 神崎蘭子. It could be a mistake, but this seems a little unlikely

10 month later update: the ranko tag got removed so I guess it was a mistake (or a bad user added tag? but I remember trying to check if it was a user-added one or not and it seemed like it was artist added)