I have no idea what's happening in the shadow on page 17. I'm going to assume fly stabbed Toifa's brain with his proboscis, which is twice as messed up now that I'm writing it. It would be time-reversible. He doesn't seem to be the main person causing humans to rampage.
Little Priest is going to have to carry the group here. He's holding the not-balloon... Pop it. Pop it now.
My assumption is that Fly is some flavor of traitor to the demon king and is doing plotting stuff. We saw Shayu's glowing mark after the ominous "she's not immune from the thing that's turning heroes" mention, and with Toifa looking up to Shayu as an idol that's probably gonna be used as some kind of trigger/control to force Shayu into "activating" against her will, or something.
Not sure how the author plans to roll this back into a romance after the reveal that the FMC is a child in an adult's body, and the MC thinks of her as such too.
Kind of burned the bridge for any believable romance to develop there.
I don't know why people are so focused on this, honestly. She's not a child in an adult's body, she's a homunculus that was made 5 years ago. She even states that not only physiologically, but
psychologically, she's 20+.
If I made a clone of myself that walked, talked, and thought 100% like me, I don't think anyone would scream about "but that's a child!" when they can't even tell which one's me or the clone made 5 minutes ago. That's the situation this manga is in right now.
All that was stated was that she was cloned 5 years ago. Does the demon king go "oh no my 5 year old daughter!" as a joke? Yeah, and then it's immediately shot down by her. It's not even like this is an "oh look, it's a 9000 year old loli vampire" situation, because she's a 6 foot tall brick house. I think most people would be fine banging an android that was manufactured 5 years ago but was otherwise a "sentient adult AI", too.
I would agree if this was a Shield Hero Naofumi + Raphtalia situation, where she's legitimately a child in an adult body (and even explains that only the body grew up). But that's not the situation here.