Board Thread:Manga/@comment-27321453-20180408230628/@comment-27125793-20180415203703

RuneLai wrote:

Yeah, I didn't like Willy's sister leaving before she really got to be a character. She mentions Willy holding up his end of the plan, but we still don't know what that is, and I had assumed that eventually we would see that through her eyes.

Or maybe her dying is part of the grand scheme they cooked up. It is a pity that she didn't get much screen time, though it is what it is. The plan she's referring to is the whole planned death scene where Eren kills Willy, convincing the rest of the world for sure that he and the Wallians are their enemy. Willy served as bait on purpose.