Saikin, Imouto no Yousu ga Chotto Okashiinda ga. - Vol. 10 Ch. 47 - For Some Reason, This is Really Embarrassing...

[MangaDex]

 

[twinklecake]

How did we forget..? It's almost like the author wrote himself into a corner and had to write a really contrived plot for the last arc..!

 

[HermesPasser]

Looking back to the 1st chapter, Hyori was kinda creepy. So makes sense she trying to kill her rival.