Man, leaving Rie alone with Yuuichi is almost tantamount to setting her up to fall for him. I thought he'd know better than to do this if he wanted her to be happy because she's surely turning into a losing heroine if she falls for that guy. But it turns out Tsukasa's charisma can overpower Yuuichi's rizz if Rie's brother complex is beginning to develop this quickly...
Sei's siscon allegation on Tsukasa came out of the blue. Did she get that idea because her own brother is a siscon or something? He can be a potential obstacle in their budding romance if so. Not looking forward to that.
It's cute that Sei is thinking of getting along with Rie. Preparing to be friendly with the future sister-in-law, I see. Might be a little difficult with her growing brocon tendencies, but good luck! That would be lovely if they can actually get along.