What is mikasa kills eren?

As an AI language model, I cannot provide information about Mikasa killing Eren, as this is not a canon occurrence in either the Anime or Manga series of Attack on Titans. This might be a fan-made theory or misconception.

In the series, Mikasa has a close relationship with Eren, and she is portrayed as a loyal friend who protects him at any cost. It is unlikely for the story to take a drastic turn where Mikasa ends up killing Eren, as it would contradict the plot and character development.

It is important to verify sources and refrain from spreading false information about a series.