@Cryotic That's Kirie's editor. She doesn't appear much, so it's not surprising you didn't recognize her. You can see Kirie get a business card from her in 143, so I guess it somehow ended up in Taihei's hands. Ironically, Bomber could have had his little sister introduce him (though I don't think he knows about her writing).
Also, there's a high schooler who appears in 185 with the same name and similar appearance, so I guess the editor also has a little sister. Like every other adult in the series.