葵「姉が…セミファイナルに巻き込まれて死んだ………」

Aoi: "Big Sis... she got swept up in the cicada die-off..."
The term "Semifinals" is a pun in Japanese, playing off セミ (Semi, cicada) and ファイナル (Final, e.g. final moments) to mean the process of cicadas dying off after reproducing. Some seemingly dead cicadas may still be alive during this process: touching them can cause them to thrash around and buzz violently. For this reason, セミ爆弾 (Semibakudan, cicada bomb) is used as an alternate term.