>>281088276
She did early on in the letters, but dropped it towards the end which is partly why Kasumi's impression of Haruyo changed. And I should clarify her speech isn't rude or rough. It fits the image of a carefree ojou-sama.

>>281088668
https://bara.shop/ha-bush/%E6%99%B4%E4%B8%96%E3%80%80haruyo/
The clear world rose, brought to you by the makers of sumire violets.

>>281088710
Igarashi made a comment this chapter along the lines of "I like designing side characters because I get to throw all my quirks into them."