User blog comment:IamJakuhoRaikoben/Chapter 480: The Northern Gravestone, Review./@comment-4933386-20160407111446/@comment-4829046-20160407113445

I'm hoping it is Kagura since it will enable her to move on and therefore understand the viewpoint of the others. It's better than having a terrible after-taste of having Jellal kill not only the original but the historia copy. Erza doing it will just baby Kagura again like with Minerva. I would much prefer for Kagura to develop immensely like Shelia did.

That's just a hope though. Not sure how Mashima wants to evoke that theme. He might want to avoid a sibling death-match or else be similar to Akame ga kill(where the siblings also used cursed katana fyi).