She's the friend that helped him pick out his ring for Hikaru, so she knows about his relationship.
It's ok, honest.
How I know this? My name is Ash. Check the credits from chapter 1.
not a bad blushing, more like a teary/crying eyes blushing. I guess she as saying something in the line "you love him, so come, lets go get him back". She's alredy have fall out of love with satou when he told her about kasabuke.
Yup, basically. Also, he's the gay one of the pair. Kusakabe is the 'bi' one. Even if he were single, the one male friend that was interested in him in the past would be more of a threat than her.
Ch. 2 chinese
https://m.facebook.com/mimionice/photos/a.249858305572359.1073741860.150920315466159/249858312239025/?type=3&source=49&__tn__=EHH-R