Kamen Rider Kabuto’s sister Kusakabesuki did not die in the play.

In the plot, Kusakabesu was kidnapped by Worm, and Kabuto rescued her, but Kusakabesu fell into a coma after inhaling the butterfly disease virus. Later, Kabuto defeated the butterfly disease virus and rescued Kusakabesu, and finally successfully treated her condition and revived her.

Therefore, it can be considered that Kamen Rider Kabuto's sister did not die, but was successfully treated.