Headscratchers / The Elder Sister-like One

• Pavlov:
  • What happened to the monster Yuu accidentally summoned in chapter 1?
    • Chiyo either killed or banished it, like the rats later on.
  • Where does that tunnel go?
  • When Chiyo was summoned in the past, what did they ask for? What did they pay with?
    • Though she has been summoned many times, we know at least some of her wishes include bringing back the dead, and some of her prices were being loved (thus the being worshiped as a goddess in the past). They didn't work out.
  • Why does Yuu keep collapsing?
    • These Are Things Man Was Not Meant to Know. Looking at supernatural beings like ghosts and Eldritch Abominations causes Brown Note effects to humans, including Yuu and his uncle, which causes them to among other things pass out. Most other cases are because Chiyo is making Yuu feel inhumanly good.
  • What do the Youkai that only Chiyo and Yuu can see do to people?
    • Standard Ghost Story stuff, and only very occasionally.
  • Black magic rats? Who bred them? Why? Are they supposed to be that ugly?
    • Probably Nyarlathotep or Azathoth given The Rats in the Walls. To do their insane bidding. I mean yeah, they're mad otherworldly gods, they don't care about earthly aesthetic tastes when it comes to their minions.
  • Do Chiyo and Yuu ever go to the ocean?
    • Not so far, no. They're just in their small rural town.
  • Who's the woman in the past who despised Chiyo?
    • One of her previous summoners. Because of The Law of Conservation of Detail, probably (Circle Triangle Square).
  • Who is (Circle Triangle Square)? Why do they talk about the powers of little brothers?
    • Implied to be a previous summoner of Chiyo who had a little brother herself who she very much loved. Due to The Law of Conservation of Detail, she potentially wished for Chiyo to bring him back after the boy died, only for Chiyo to be unable to, leading her to hate Chiyo, but nothing is set in stone.
  • Is the Watermelon monster still in the backyard?
    • No, the backyard is cleared in later chapters. Chiyo seems to have killed it to take all the watermelons.
  • Who needs/wants the letter? What's in the letter?
    • Yuu thought it was his uncle's insurance card that he had to give to the hospital to cover his treatment, but it was in fact a letter he wanted to give to Haru, who he thought at that moment was his cousin / Yuu's mother. Haru had already taken the letter after Yuu's uncle summoned her though, so Yuu never found it.
  • In the picture of Yuu's uncle as a child, who are the people who were torn off?
    • Yuu's father / his brother.
  • How did Yuu's parents die?
    • Car crash.
  • Did Chiyo know Yuu's mother and father? Was her name (Circle Triangle Square)?
    • No, (Circle Triangle Square) is implied to have lived centuries ago.
  • Why was Yuu crying that time?
    • In The 13th Night, it's because he realized that he really is, after years of emotional abuse, of bullying, of depression, truly happy again.