Omg thanks @im-ps2, I'm really glad you liked the new chapter!
Mimi is just meant to be one of Aiura's old gyaru besties from the school she used to go to before P.K. Academy. Given how social Aiura is, there's no way she didn't have a friend group before, y'know? Though presumably Aiura's old friends didn't have psychic powers or she would've brought it up at some point!
I was just thinking about how difficult it must be to have a really exciting relationship but not be able to talk about it at all with any of your friends because of all the secrets involved. Like how do you not mention such a big part of your life?? That would be hard!!!
So it was partially a challenge on how Aiura could get an accommodation for her extrovert nature here, just as Saiki gets several accommodations for his powers throughout the series.
An old friend who's moved to another country and has never met Saiki sounds like a pretty safe bet, especially if Aiura translates the magical stuff into more mundane situations. Mimi is just the name of one of my own friends who I love talking to on the phone lol.
Also yeah, I just love writing conversations and thought it would be fun to be a fly on the wall for such a wild story! <3