This young lady has been around for a long time, but somehow it took her quite a while to finally show up. Little Secchan was a gullible scaredy-cat who used to start crying really easily, but nowadays, she's a bit tougher. She's also starting to become a young fashionista who's very much into nice clothes and accessories, which is a problem for someone like me, who has no clue about what is fashionable... ;;;

Shiori: "...but not all of them made it. Later on, when the police finally arrived at the scene a few hours after sunrise, they found-"
Taku: (...I remember now.)

We get to see a glimpse of Taku's memories, showing the crying little girl from earlier.

[Introduction: Kogarashi Setsuko - "Secchan"
Taku's neighbor and oldest childhood friend.]

Setsuko: "-they found several bodies! And even after six years, someone's still missing! Nobody knows if they are dead or alive!"

She holds up her phone, which shows a news article on the topic.
[Police were... ...to a secluded property in the forest of Sayagimori in the early morning hours, alerted by one of the students who had managed to flee from the attacker and leave the forest. Upon their arrival, the police found several bodies, two... ...didn't show any...]

Taku: "Uh... sure, that sounds awful. But why are you even looking at stuff like that?"