
I think the mangaka probably thought it was a good disguise so people would just think it's a feather curling on Set's wing, but man alive... I never thought I'd see this on the bottom panel:
http://www.mangago.zone/read-manga/legend_takano_masaharu/nmt/mpn_chapter-2261994/pg-22/

Which are sad and messed up, but I love the expressions. Anyway, here's my general thoughts:
This story is a bit disjointed in the way it's written/drawn. The "brother" originally said that he offered to be rented, but then the other version has the little girl asking to rent the "brother."
A few comments below, someone said that the earlier (blurry) chapters could have been drafts, which makes sense because of the somewhat drastic art changes in terms of color and shading on chapter 7. And chapter 7 onward doesn't match the timeline before from chapters 1-6.
I honestly adore this story. With the whole "rental" thing, some people may have found it creepy or concerning, but so far the rental brother has been just like a brother as intended. I find this heartwarming yet tragic because of the girl's situation and she's doing so well to hang in there with help from the rental brother despite the hard times with her real brother.
I have this feeling with the roommate's fashion design for Ianna that the bids are going to skyrocket when the "slave" auction begins, but that's only if the design department's event is being held before the swordsmanship competition.