In every adaption, Takeru is killed by the Line-crazed Keisuke, and the knife is taken as a symbol of proof. Keisuke then uses the knife to kill many people, including non-participants in Igura, and attempts to kill Akira with it.
In the Game Edit
The knife appears on every route, and both Takeru and Keisuke have sprite images holding this knife. Takeru’s knife also appears in several CGs.